A secondary is failing to perform the initial sync with another secondary to join a replica set.
It fails due to a socket receive timeout when talking to the other secondary during the initial sync.
I have attached the final lines of the log from the secondary trying to join the replica set.
NB: we never see any "network problem detected" lines in our logs, so it seems as if there is never any retries:
I think the SocketException due to the timeout is being caught earlier:
which then triggers the assertion exception
I do not believe the fix in https://jira.mongodb.org/browse/SERVER-9528 was correct due to the exception swallowing.