When a stale mongos gets a moveChunk command it first does a refresh. However a mongos might have refreshed from a stale configsvr secondary that has not seen the latest split / merge operation on yet.

The mongos may not yet know of a clusterTime inclusive of the split because another mongos did it, so there is no causal consistency guarantee.

For a moveChunk operation the shard will later throw a StaleShardVersion error here.

However the mongos will not retry the operation because this code is missing the StaleConfigInfo extra information, which causes the code in strategy.cpp to abort a retry attempt.

Possible solutions:

• Attach StaleConfigInfo to the exceptions on the shard
• Perform a version check on the configsvr