Animated Mask Path Gets Stuck on First Keyframe

Working on a pretty simple scene with a person talking in front of a logo. Because of the layering of the footage, I have the logo placed on top with it masked out to cover the old background. There are several parts where the person moves in front of the logo, so I need to keyframe the path of the mask to move so that it doesn't cover his shoulders. But for some reason, the mask path is behaving strangely.

The bounds/handles of the mask seem to be keyframed in different positons as expected. But the mask itself isn't following the shape - it still shows the same amount of white space as the first keyframe even though I shrunk it down in the second keyframe. It's like it just ignores any keyframe after the first one, even though Premiere's UI is acting like the keyframes actually exist. It's very odd. I've attached an image to illustrate what is happening.

I tried nesting it in a sequence like I saw suggested in other posts, but it didn't seem to make a difference. Any idea what's happening here? (I'm on Premiere Pro 2019, Windows 10)