I've decided to post a report here because it should be harder to lose track of than of the thread in "EditingHelp/Scripting".
The source code currently has a function to check if the current menu is animated, but it's not called from anywhere. This is where it's called in Raze source. I can fix this issue locally in GZDoom by modifying the code of TryRunTics in the same way: replacing "r_NoInterpolate" with "(r_NoInterpolate && !M_IsAnimated() && gamestate != GS_INTERMISSION && gamestate != GS_INTRO)". However, I'm not sure whether the gamestate checks are Raze-specific, so I can't make a PR at the moment. Leaving this for Graf or other devs to resolve.