By using the repro mission on a dedicated server, jump in the M4 Scorcher artillery tank as gunner (don't get inside as driver otherwise test will not be good => locality of vehicle goes from server to player computer).
Execute the following command on server and player computer and notice it fails on both cases (ammo count stays at 32 instead of going to 10):
vehicle player setMagazineTurretAmmo ["32rnd_155mm_mo_shells", 10, [0]]
Note: for execution on server you must first run: myv = vehicle player; publicVariableServer "myv"
then
myv setMagazineTurretAmmo ["32rnd_155mm_mo_shells", 10, [0]]