[tehmoku]

So, here is the code for running on a throttled OnUpdate (just change the update interval to whatever you want).

Note: I only really care about raid frames being highly accurate, and I left the target frame how it was.

Fair warning, it's quite a bit more taxing on your CPU. It's a lot more reliable though, and probably what I will be using. This code is for legion, but just remove the underscore next to buffName on line 21 and it will work for BfA.

local ONUPDATE_INTERVAL = 0.5
local lastUpdate = 0
 
--Compact Unit Frames
hooksecurefunc("CompactUnitFrame_OnUpdate",function(frame, elapsed)
lastUpdate = lastUpdate + elapsed
 
    if lastUpdate >= ONUPDATE_INTERVAL then
        lastUpdate = 0
 
        local index = 1
        local frameNum = 1
        local filter = nil
 
        while ( frameNum <= frame.maxBuffs ) do
            local buffNames = UnitBuff(frame.displayedUnit, index, filter)
            if ( buffNames ) then
                if ( CompactUnitFrame_UtilShouldDisplayBuff(frame.displayedUnit, index, filter) and not CompactUnitFrame_UtilIsBossAura(frame.displayedUnit, index, filter, true) ) then
                    local buffFrame = frame.buffFrames[frameNum]
 
                    local buffName, _, icon, count, debuffType, duration, expirationTime, caster, canStealOrPurge, nameplateShowPersonal,
                    spellId, canApplyAura, isBossDebuff, casterIsPlayer, nameplateShowAll, timeMod, _ = UnitBuff(frame.displayedUnit, index, filter)
 
                    if spellId == 33763 and casterIsPlayer then
                        local timeRemaining = (expirationTime - GetTime()) / timeMod
                        local refreshTime = duration * 0.3
 
                        if not buffFrame.highlight then
                            local highlight = buffFrame:CreateTexture(nil, "OVERLAY")
                            highlight:SetTexture([[Interface\TargetingFrame\UI-TargetingFrame-Stealable]])
                            highlight:SetPoint("TOPLEFT", -3, 3)
                            highlight:SetPoint("BOTTOMRIGHT", 3, -3)
                            highlight:SetBlendMode("ADD")
                            buffFrame.highlight = highlight
                        end
 
                        if timeRemaining <= refreshTime then
                            buffFrame.highlight:Show()
                        else
                            buffFrame.highlight:Hide()
                        end
 
                    elseif buffFrame.highlight then
                        buffFrame.highlight:Hide()
                    end
 
                    frameNum = frameNum + 1
                end
            else
                break
            end
            index = index + 1
        end
    end
end)