I kind of thought that's what you meant in your other post...but thought, nah, he couldn't mean that. That's definitely not normal.
I.e. you put it all together, pull the trigger (shouldn't matter if it's plugged in or not) and it moves out of position (i.e. it's not pivoting on it's axle but rather moving around loose?)?
Or you pull the trigger and it doesn't spring back? Take a closer look at how the trigger spring is installed. The short end hooks to the trigger through a hole just above the trigger blade (may be hole, may be a slot). The coil wraps around the left side of the axle. The long end rests on the inside bottom of the mechbox shell...just under where the wires are soldered. the trigger should held forward by the spring.
A common error is to put the short end of the spring under the trigger vs. though the hole. If you do that it usually won't move far enough to complete the circuit.
Either way...if it's shooting in full but not in semi it's the cutoff lever operation.