I always work on the default time format.

Usually if I move by one frame after 00:00:00:29, it then goes 00:00:01:00

But now, for some reason, the time has been doubled after working on a project for over two weeks.

After 00:00:00:29, it goes 00:00:00:30 and up to 00:00:00:59 and then it reaches 00:00:01:00

I'm sorry if I made it confusing due to my limited english vocabulary. Thank you.