From the entire log, there seems to be 3 systems affected. UIDropdownMenu, MultiActionBars, and CompactRaidFrames.
The UIDropdownMenu system has always been hopelessly tainted. It's a surprise Blizzard's own code doesn't taint it at times, which probably gives them the most headaches.
I don't have an answer to what could be happening with MultiActionBars, I haven't done any testing previously with them. The only advise I could think of would point to the following section of the stack.
Code:
pcall()
Interface\FrameXML\InterfaceOptionsFrame.lua:217
securecall()
Interface\FrameXML\InterfaceOptionsFrame.lua:252
This raises more questions as
InterfaceOptionsFrameCancel_OnClick() is running
securecall() in iteration of the secure local
blizzardCategories through
InterfaceOptionsFrame_RunCancelForCategory(), which is just a
pcall() wrapper for the associated cancel method.
CompactRaidFrames has had problems with
CompactRaidFrameContainer_LayoutFrames() in combat ever since the system was introduced with Cataclysm. Even to the point where it throws errors and glitches out when a party member joins or leaves or if a pet/minion is summoned, both while in combat and does so with no addons loaded.