Fast Blur and Mask Separating?

TL;DR: Using fast blur and then mask forwarding. Mask forwarding isn't perfect so I go back to adjust the mask on a couple of frames. When I do this, the polygon mask shape and the blur effect separate. Cannot bring them them back together. Can only move the mask shape, not the blur. Not sure why this happens or how to fix. What am I doing wrong?

Phone number field example below.

I'm using Premiere Pro CC 2018 to censor/blur out sensitive information in screen recording videos. I add an adjustment layer on top of the clip, select the fast blur effect, draw the mask over the sensitive data (i.e. phone number), and then adjust the blur level. I then track the selected mask forward so that it follows the data as the user scrolls down on their screen. Generally this works but occasionally it's not perfect and I have to adjust the mask on some frames. Not a big deal as my videos tend to be short.

Lately, when I attempt to adjust the position of the mask to touch up what the mask forwarding missed, the blur effect and the mask appear to separate. It's as if the mask polygon I drew and the blur effect became two separate things. I am unable to move the blur effect, just the mask. Nothing works to fix it, so I delete the mask and start again. Sometimes this fixes it but for the past couple of hours it has not worked.

Any help or step in the right direction is sincerely appreciated. Could not find another forum post about this after searching for an hour, but may just not know the right terms.

Thank you!

JD