Why does attempting to animate Grid Panel's fill rule causes the engine's RAM usage to explode?

So I’m trying to give more animation to my RPG status bar UI, which is stacked with Grid Panel. However, attempting to keyframe the grid rules causes the engine’s RAM usage to (quite literally) explodes from 1 GB to nearly 7 GB in an instant, and it stays there until it freezes my system entirely. This behaviour happens every time, persist across all 3 minor versions of 4.22, and I think it’s reproduceable. This makes loading 100 big sub-levels at once a tame job compared to keyframing a UMG Grid Panel.

With a bit of luck, this time my system is free from freezing after a while, without abrupt shutdown, and UE4’s crash reporter finally came out, but it has no idea about this behaviour, thus reporting about it having no debugging symbols or whatever.

What actually caused this to happen? Should I migrate to 4.23 to solve this issue (which I’m trying to avoid, preventing all the C++ scripts and add-ons from breaking), or just simply revise my UI guidelines to avoid animating grid panels in the first place?

Hello,

We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.

https://epicsupport.force.com/unrealengine/s/

Thanks

After filing the bug report, the option to keyframe Fill Rules in 4.22 was indeed already removed in 4.23.
Guess they’re never meant to be animated, after all…