Use of countdown timers

What I did: Set up a protocol containing countdown timers

What happened: Everything went fine, until the time I needed to use it.

What I expected: That I coud freely reset the timer and use it again. Instead, it got " locked" after the first run. Almost like if i could use that timer only once.

Things that might be helpful to know (Findings version, OS and model, etc):That happened using in IOS. In the mac I could reset the timer, but it was not an intuitive process. I had to edit the countdown.