True.I noticed 2 things with that Netplay.
1. Both players must use the same Kaillera plugin (the first build in this thread has other one)
2. Both players must have the same version of Dolphin (if one have x64 and secon x86 it's impossible)
3. Both players must have the same revision of Dolphin
Also, sometimes wrong game starts for second player, but why it's unkown (at least for me)