IPSEC VPN to pfSense

I just bought a RB2011UAS-2HnD-IN and experiencing some weird Problems with IPSEC VPN to multiple pfSense endpoints. Everything seems to work fine when I just activate one Tunnel. If I enable all of them the whole ipsec crashs and no tunnel is active. Anybody got the same problems? Tried ROS 5.25, 6.0 and 6.1.