When I regenerate, I have 11 more regenerations but if I right-click on the Watch, the number of regenerations resets itself to 12
I don't think it's normal 😅
Forge 36.1.0

But it isn't logic : Timelords have only 13 lives (and 12 regenerations) before they die (except the Doctor).
So the watch can give us 12 lives and we have 12 lives by default ? So 24 lives in total ?

You should not have 12 lives by default unless you have that enabled in the Config option.
The watch is way for users to obtain more Regenerations when they run out and to store their regenerations within.
You are always capped to 12 lives at once.

Ok thank you !
So this isn't a bug

Yeah, it is not a bug

This is not infinite, notice how the watch damage decreases
It does not reset to 12, it takes 1 off of the watch
If you had 6 and the watch had 12, 6 would be taken from the watch, meaning the watch would now have 6 and you would now have 12