My wife uses a Lemo and has connection issues from time to time with her iSticks.
Seems we have the best result adjusting the 510 pin on the Lemo so it just
barely extends past the
threads. If you have not previously adjusted the 510 on your Lemo, remove the base, hold the internal lug in the base with a pair of needle nose pliers, and then unscrew the 510 contact screw. It will adjust easily after that.
Also it appears that it's possible that the base section on your Lemo is not fully tightened, which could also cause the problem.