Link it from wowhead.

Mine turned out to be a Isle of Thunder quest that was on the level 91 character I was having trouble with. As soon as I dropped the quest my FPS went back up. Turns out my 100+ character is fine since he wasn't running the wardens quest.

Quest:
http://www.wowhead.com/quest=32707

I ran into this problem today as well. My FPS dropped into the 5 - 15 range while playing on my 110 Shaman. Everything went back to normal once I disabled the Carbonite Quests addon.

I've also noticed my minimap is acting a bit differently as well. For some reason, some of my icons are huge, and some of them look as though they're cut in half. Here's a screenshot of what I'm seeing.

I'm having the same problem, it's only on my 110 character that I have the framerate issue and it's only been a thing since after I unlocked WQs, I thought it was a different addon (broker world quests) at first since it was the only thing I'd added. It's been on and off since then (which is a week ago now) so it could very well be a wardens quest thing, which I didn't do and thus got moved off the map. I'll go do the warden's quest and edit this to say if it fixes it or not.

Edit: Upon death of the 4th wanted, framerate spiked up to 30. Heading to turn in the quest and see if that gets me back up to 90.
Edit 2: Nope, quest completion stayed at 30fps, but map open still brings me up to 90. Very confused but at least my framerate is better.

I didn't even noticed that the blizzard map brought the framerate back up until someone else pointed it out. Map open gives me 80-90fps map closed gives me 10, it was giving me even less but i disabled other addons trying to find the problem that got it up to 10. I can only guess with the map closed it's trying to reach info it can't get about world quests.

After logging in today the issue is back and it seems today's Emissary quest is Wardens again, seeming likely it's the cause... somehow.

Update: Can confirm it's caused by an incomplete Wardens Emissary quest, the moment I got credit for the 4th Wardens World Quest my FPS returned to normal. Don't need to turn in the quest it seems, just complete the requirements.

Not sure if it should be mentioned but I did also have some lesser FPS drops the other day (100ish down to 70ish, rather than the 100ish down to 15ish that this causes) that MIGHT have been caused by the previous Emissary quest (Kirin Tor? Can't remember) though it could also be completely unrelated.

It probably has something to do with WQ and Carbonite trying to parse them / draw them on the map, I know the emissary quests appear in the quest log, but they are not real quests and should not be there, nor should they be in blizzards quest log, but they show up in the watch "x/4 world quests done" for each faction available.

The issue trying to find the problem and fix it is on my 110 it's never happened and hasn't happened :( I'm leveling another 110 now to try and get it to happen (109 so hopefully by end of weekend)

Ohhh that might be why I'm stuck at 30 instead of 90fps. I'll see what happens when I finish off kirin tor later, just have one left.

Edit: My fps went up to 50 upon completing kirin tor, and has kinda been fluctuating upwards since then.

Thanks for working to get another one up there Rythal.

I turned the quests module back on after completing my emissary quest this evening. My frame rate boosted back up to within 10 fps of my normal range. I will check again whenever I get my next emissary quest later today.

I'm still having the issue with the mini map though. Even on my lower level characters, the icons / gathering nodes are definitely not working like they were yesterday. It's almost like a portion of the icons are cut off or a piece of the blizzard map is showing up instead of the carbonite version. Any idea what's going on with it?

I just completed my Wardens emissary quest and the frame rate did indeed shoot back up to normal. Seems like the Wardens emissary quest is somehow related.

Good luck, Rythal. I know this sort of bug is a nightmare to find and fix.

If all else fails, though, I have a suggestion. Call it a feature! "Carbonite will now encourage you to complete your Wardens world quests by lowering the fps until you do."


Update:
FPS dropped again sometime later, as I began other world quests.

LVL 106 and having this issue
 

I haven't even gotten past 106 and i haven't been able to use the quest module. I really want to but the only way to fix my fps at this time is to turn it off. Let me know when there is a fix for this because I love this addon. Thanks for your hard work

There is fix for this issue on Carbonite GitHub repository, download latest version (link in my signature).

Tested it and fps are better after this Rythal commit.

now maps is not working either. still have the low frame rate, as in playing on my moms 12 year old lap top kind of frame rate. i have 16 gigs of ram and a gtx 970, and a I 7 3.4 ghz so it's not my machine. did a clean install of the current master file. so i don't know what to tell you. my map is solid yellow, and the low frame rate.

Fixed the fps issue, it was an incompatability with the new Lightheaded Addon. maps still are yellow using the master file, but if i update off of curse it's fixed. go figure

Download latest version from github, disable all addons except Carbonite and check if issue persists. There might be other incompatibilty. Rythal fixed problems cousing fps issues with quest module.

Thanks Rythal for the quick fix! :)

Rythal, you're a god. Thank you for making the fix. Playing WoW without Carbonite Quest has been a bitch!.

Thank you to you and your team :)


Edit 1: I can't abandon an Emissary quest.. Well it was an Emissary quest, but the questlog says it's a Pet Battle Quest in Dalaran for Stitches Jr. Jr. I just killed that pet in a pet battle and now it's changed. Clicking on the quest it says: Court of Farondis.
I tried abandoning it, which did nothing. The quest is still there and showing the wrong thing.

Edit 2. Something is up with Carbonite Map... when scrolling out to see more of Broken Isle than just Dalaran, moving the mouse between different areas sometimes makes Carbonite Map flash green.. It started early yesterday for me, but I thought it was because at that time I didn't have Carbonite Quests turned on. Now that I have your new fix for Carb quests it's still there... also the icons for where like normal quests, WQ's and other stuff are on the map seems to be "stuck" on parts of the map so when you use the mouse to move the map with the icons follow suit, instead of staying where they're suppose to be or was when you opened the map the first time around. Sometimes they swap back to their original place when you close or minimize the map, but not always.
I've saved the old files from before the most recent Carb quest fix. I'll try and and swap the new one for the old one and see if that makes a difference. Either way I'll report back with another edit.
Edit 2a: Swaping the new carb map for the old carb map did bring back the ability too see many more WQ's on the map. with the new map I was only able to see the pvp WQ's and not any others. With the old carb map the flashing of green stuff mousing between fx. Azsuna and Suramar is much more prominent than before. But at least the icons are sticking to where they're suppose to be and the fps is normal so no lag either. Adding a screenie, so you can see the the green flashes I'm talking about.
http://i.imgur.com/iZt6R4G.jpg

Suggestion: Maybe instead of changing Carb Quest too much, add yet another addon and name it Carbonite World Quest, that would work with Carbonite Map and Carbonite Quest but not make it mandatory to have so those who's unlocked WQ's can use it and turned off on a toon that's not unlocked WQ's yet. It's not to add to your workload, it's merely an idea that popped in to my head the other day.

Emissary quests I need to treat special, they shouldn't be in the quest log... but for now they are. You can't abandon them because they are world daily quests and not something you pickup or abandon.

Green flashing has actually been happening since launch, it's caused by missing texture which quickly gets replaced and shows... haven't found yet which texture it is

World quests on the map, old one showed them all because it considered them bonus quests, the code turning them into world quests is only just started which is why on the new one it's just PvP and Pet Battles.

The new version that I downloaded seems to have taken care of the fps issues as far as I can tell. I also haven't had the icon / minimap issues since changing the glow delay setting as suggested.

However, now I'm running into a different issue. The quests don't seem to be syncing up right. For example, if I complete a few quests and turn them in, the question marks are still on the minimap after doing so. The auto completing quests, where you do the "click here to complete" in the quest module, don't seem to be showing up at all. I have had to use the blizzard log for these ones.

I have The Wardens today for the first time and got slammed with the lag. Finished up the four world quests and turned in to Marin Bladewing and lag vanished. Chat log indicates the final "quest" was called "The Wardens" (log says "The Wardens completed.").