Mmm, I have netgen that's hanging without listing symmetries. I mean it's been running for 8h ... I know it's going to fail because ... shorts in routing so this is really just an experiment. It's stuck at :

Circuit contains 76441 nets, and 21 disconnected pins.

Circuit 1 contains 671968 devices, Circuit 2 contains 671968 devices.
Circuit 1 contains 76435 nets,    Circuit 2 contains 76441 nets. *** MISMATCH ***