I have the same behavior with my Oudie 6.1 and the Flarm 5.09 connected via a MUX from K6-Team. In flight modus, everything is fine in SeeYou, but ConnectMe identifies the Flarm, lets me have the flight list and subsequently hangs up.
Delogging the Flarm via SeeYou on a PC is fine, though.

I somehow suspect the Flarm data cable to be crappy or wrongly routed. I had a very similar problem with the CAI302: The original cable which came with the Oudie is quite long, so I wrapped it up and fixed it with cable tiers.. Same symptoms as above (SeeYou Mobile working fine, ConnectMe identifying the CAI, but no downloads). When I straightened out the cable, everything was fine...