HELP: Masks the wrong shape

[enabiah]

Hi there. For some reason any mask shapes I cut out on my image or video clips are not the right shape. See example below for an opacity mask I created for a video, as well as its settings.

I previously posted here thinking this was a problem with a mask for a specific effect, but it turns out it's happening to any mask I create in Premiere.

[Phillip Harvey]

Is the mask applied to a clip or an Adjustment Layer?

Does the clip have Time Remapping on it? Any other keyframes?