I haven't flown LH directly from MUC to the US for quite some time. IIRC the second security check was not mandatory, but more kind of a SSSS related thing. I remember that I have passed a check point in H where they did check the docs and if everything was fine you could bypass the security check. Am I wrong here?
Any reason why departures from FRA don't require the check and the ones from MUC do?