My pomodoro clock is pausing after I try to update the values while the countdown is running

I just finished a stopwatch clock challenge, however I seem to have troubles when I am updating the time of the session while the clock is working. I created two buttons in order to update the value.There is also a start button and a pause.When I start the countdown everything works fine but when I press the the add(+) or subtract (-) button twice or the combination of both, it updates the value but it stops the countdown, it just works when I press either button the first time. If I want to keep going up or down the value changes but it stays frozen. After that, I have to press the start button and I don’t want that since I block the start button to be pressed again after the first click. The start button just unblocks when I hit pause. So in order to get the times going when the problem above happens I have to hit the pause button, which at that moment I wouldn’t need it but that event unblocks the start button, and then hit the start button. It is not user friendly sort to speak.
This is my project: