Exporting to video creates insanely big file

Hi there, i'm finally exporting an animation i've been working on for 7 months now, the animation is about 10 minutes long and the .fla file is about 300mb, i'm currently using animate 23.0.2. During export, which is hvec and the youtube 1080p preset, the progress bar gets to 86% and hangs, i can see the scratch file it's been slowly increasing throughout the day. It is currently at around 307gb and no sign of slowing down. What gives? Is this some sort of storage leak? is that even a thing? I had to symlink just to get it to do this on my big drive because it was eating all the space on my windows drive and running out.

I guess my question is, is this normal?