Sometimes a sender cannot find a message with a seqno as requested by a receiver. The seqno requested (47176) was already purged, sent_msgs: [48059 - 48090] (32)

This could be either an issue in STABLE, which prematurely purges messages although not all members agreed on the highest seqnos seen, or NAKACK, which might incorrectly 'change' seqnos. Very hard to reproduce !

Trace:
42032 [ERROR] [OOB Thread,perf,10.68.32.33:32968] NAKACK.handleXmitReq(): - (requester=10.68.28.33:33763, local_addr=10.68.32.33:32968) message 10.68.32.33:32968::47176 not found in sent msgs [48059 - 48090] (32)