Censoring moving objects with Premiere Pro

Hello,

I have created a video via Adobe Rush. It lasts about 10 minutes and is completely edited. Now I want to use Adobe Premiere Pro to censor some faces afterwards. So far so good. Effect applied to the track, mask created and face censored including tracking. However, the blurring can now be seen throughout the clip, even where it is no longer necessary and should not be.

Can anyone tell me how I can limit the blurring in time?

Best regards