Then it's a different issue, poor contacts, motor wires loose, or something else.
As for stalker, every pull of the trigger is a differently timed cycle.
Not to get too technical, but as stuff heats up, electrical resistance in the system rises as well, meaning less voltage. Not an audible difference, but enough that it would causes the sector gear to stop a few teeth early, and possibly right on the cutoff lever.
Not to mention the motors we use are FAR from perfect lol
The best solution I've seen to this issue so far is an SW-COMP with active braking. Then as long as your making full and complete trigger pulls in semi, your piston is ALWAYS stopping at it's ideal rest point (IE the point where you don't need to hit the anti-reversal when disassembling the mechbox)
The only other thing you need to watch out for is what Amos and I refer to as 'cycle overlap'. Most common when running heavy, torque up gears that carry alot of momentum(prometheus), weaker springs (<350fps), motors with low magnet strength (G&P M120 or any stock motors really) and large batteries (9.6v large), which also happens to be the exact setup I had at a scrim lol
Anyway you hear it spool up from 900 to 1200rpm, then when you let go of the trigger the gun 'runs away' for 10 rounds.
Also cured by active braking SW-COMPS, but the reason I bring it up is because it too can cause stoppages when switching from full auto to semi auto in AEG's....and it's annoying lol