First of all if you get in gunner whether or not tank is local to you or server, the engine starts and here is no option to switch it off unless you switch to driver. So I think it should not start when entering gunner seat.
If you exit gunner seat while engine is on, it will not switch off if tank is local to you, but will switch off if tank is local to the server, but in this case working exhaust effect will continue (only if tank is local to the server)
Start dedicated server
log in
spawn one M4 scorcher on the server and one on the client
Enter gunner seat on each of them then exit. Observe engine operation and exhaust effects.
Update. After some more testing, it looks like that the sound of engine running is simply not playing when tank is local to the server. This is how to test it:
Spawn M4 Scorcher on server call it tank.
Execute on server side
tank engineOn true
you can hear the engine started and see the exhaust smoke, then it goes silent and only smoke is visible, but in fact the engine is running. trying to execute tank engineOn true again makes no difference.
Execute on the server side
tank engineOn false
You can hear the engine shutting down sound and this time engine is turned off properly and no smoke to be seen.
If you get in Scorcher as driver, start engine then eject to keep it running then log out and log back in on the persistent server, the Scorcher will appear to be silent. The Scorcher will be local to the server, transferring ownership back to client will reveal working engine sound. Basically JIP wouldnt be able to hear working engine until they get in driver.
I don't know how tanks work, so please correct me if im wrong, but I could imagine that you need the engine to turn the turret. In that case the engine should activate.
Mass-closing all resolved issues not updated in the last month.
Please PM me in BI Forums (http://forums.bistudio.com/member.php?55374-Fireball) if you feel your bug was closed in error.