Army on uprising province

If they are not in the province center they will still be yours.

I usually do that and just recapture provinces if I only have one unit and not enough to prevent rebellion.

I just added that to my complete guide on morale and rebellions

https://forum.callofwar.com/index.php?thread/21166-complete-guide-to-rebellions-and-province-morale/&postID=140159#post140159

Thanks for confirming that.

I have a stack of 40 units in a province (defending artillery) but it shows the army strength is 0 and the up rise is 100%.

if I move and I will lose the fortification bonus if not I am concern it will up rise and the stack will become emery.

If you are not at the province center in order to prevent revolt I think you will also not have the defense bonus from the fort.

The unit is in the centre and the system tells me my units get the bonus. I just wonder why the province Army Strength is 0.

Odd

Is it your province or an allies?

that's mine and I found out when I point the army to attack (shelling). the province army strength turns 0 but If I cancel the attack (while it will still fire the shell in defence), the army strength comes back.

It must have to just move enough to fire that it leaves the fort.

There is a "snap to center" kind of deal where units move to the province center if they are within a few KM of it. This is necessary for grouping units together, otherwise you would likely have a crowd of 6 infantry if you sent each one to the province center, instead of a stack of 6.