Backdrop border corruption
 

If I switch back and forth in my profiles, this happens. Using an addon I made.
http://prntscr.com/bbbsn3

And I never seen this happen on live. And I been trying to fix this, no luck yet.

Does your addon have any code?

A ton of it, just not sure what part to show.

Is this a custom border? Every border parts need to be at the specific coordinate location, if you want to use SetBackdrop type borders.

This is with normal borders, but I think I may have found a cause. When I switch to a different profile the same bar is getting animated scaled in with onupdate and setscale. And during that time I think i'm doing SetBackdrop(). I may have to pause the animation set the backdrop and resume.

This scaling animation been a thorn in my side cause I cant use blizzards built in one to do it :)
Took me days just to get it working, without bugging out other parts of my addon.

Going to chalk this up to a beta bug I think. Bars that are not even getting animated are some how getting corrupted from the one that is. And the animation and the setbackdrop is not happening at the same time. Maybe next build will fix it.

There's no custom anything being used, its all blizzards own textures.

Well I fixed it, more like a work around. After a profile is changed. I do a C_Timer.After with an extremely small wait time. To do an update on the next frame. The I redraw the bar.

When using blizzards built in animation group scaler the glitch goes away.

The only difference is I use OnUpdate. I create an AnimationGroup to an empty frame. Then I still do AG:Play(), and I do AG:SetScript('OnUpdate'), then inside the onupate I use Animation:GetProgress() and calculate the scale and do a SetScale on the frame I want to modify. if blizzard ever changes their built in scaling to work. Then this problem will fix its self.

For some reason when I stop animation, and draw the bar all in one cycle it glitches out. This mod is very big and does many things. I found stuff like this before when doing stuff with frames in one cycle.

If you have sample code that reliably reproduces a Blizzard bug, please provide it so it can be reported through the proper channels. If it only occurs in the context of a larger or more complex addon, I would be happy to take a look and reduce it to a small test case for bug reporting. Feel free to PM me if you don't want to post your work publicly. A workaround is great news, but a true fix would be even better. :)