Hey,
So I have noticed this on the following occasions:-
(i) My Mortar gets taken out by the enemy, the base stays out of action until I respawn.
(ii) The enemy circle in on my mortar looking for me and I'm forced to leg it to another location, and move out of range (which differs) of the mortar base.
(iii) Ammo replen forces a redeployment.
(iv) Standard death
I'm not sure if the above link into your experience, I know its frustrating at times, but I think there are certain scenarios where a forced mortar redeployment is triggered after the re-balancing due to unfair advantage of ammo crate & mortar usage.
So, I can tell you how it works: once you plant a mortar, a timer begins. To be honest I don't remember if it's 45 or 60 seconds. One way or another, after that time passes, mortar is 'replenished' in your loadout, no matter what's going on with the old one. However, there is also another, 15-second timer that starts when a new mortar appears in your loadout. You can only place a new mortar once that 15-second wait is complete. Main purpose of that 15-second timer is not letting people to deploy a mortar instantly after spawning, but what you experienced is one of the side effects. I hope that I explained it well enough.
Ah, and that 15-second timer starts from zero on every single spawn.
