Ipv6 packets that are natted get dropped due to Udp6InCsumErrors

Issue

The architecture involves utilizing keepalived LVS in DR (Direct routing) mode to load balance UDP packets sent to the LVS VIP to 3 or more virtual servers (per packet round robin - lb_algo rr). We also apply a redirect rule in ip6tables to translate DST IP from VIP to RIP (Real IP).
The UDP packets (Radius) seem to get load balanced fine by LVS Server. When they arrive on the Real Server they are dropped and never arrive on the application.

The drops correlate to the following counters in 'nstat':

# nstat | grep Udp
Udp6InErrors                    10                 0.0
Udp6InCsumErrors                10                 0.0