[HELP] Can't frame interpolate 4K footage to 60FPS

[acoolrocket]

For some reason whenever I want to frame interpolate any 4K footage (just simple .mp4 encoded with Media Encoder), it would just stay at 0% unlike 1440p or lower that would automatically start with no errors.

I've tried with both Avisynth and Vapoursynth to no avail:



Also use AVC level 5.2 and nothing extra in the settings, just plain frame interpolation. Using version 2019.08.26.1 too.