Leaver Buster timer freezes

Sadly I don't have a picture of it. Most likely will add it on once it happens again. Basically, I have leaver buster and when I wait for 20 minutes, around 15-18 minutes, it freezes. Not sure why and what the reason is. It has happened to me 3/5 times I waited for 20 minutes and I didn't bother getting a picture.

Tried searching for the same problems and couldn't find it on the boards so I decided to make my own.