“I updated from Enyim.Memcached 2.11.0 - https://www.nuget.org/packages/EnyimMemcached/2.11.0, so the 1.2.X changes may be relevant”
Ah! That’s actually a separate fork of Enyim.Memcached that we don’t maintain at Couchbase. If possible, I would try to upgrade your client instance as well - just swap your MemcachedClient instances to CouchbaseCient, the interfaces should be the same, but you’ll get a more updated fork of Enyim.Memcached since the CouchbaseClient sits on top of it.
Switching to CouchbaseClient will likely resolve this issue, since it’s using a different socket pool implementation.
Thanks,
Jeff