windindd using huge amounts of memory on RHEL5

Issue

Have an issue on a server where winbindd consumes large amount of memory:

PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
19839 root      15   0 2458m 2.3g  59m R 36.9 59.4   2895:04 winbindd

Winbindd is also consuming a high amount of CPU and generating a large amount of traffic to the AD servers in comparison to other servers with the same configuration.
A service restart clears it, but this seems to occur on a regular basis.