I see here few issues:
1. Version 2.3.3.1 explicitly doesn’t support ESX 6.0, it supports ESX 5.5 only.
2. IPoIB multicast on 2.3.3.1 (assuming you will move to ESX 5.5) use DMFS (flow steering) by default.
3. Need to verify that you use the latest FW mentioned in the Release Notes (last GA ConnectX-3 FW).
I hope that it helps.
Ophir.