There are certain code paths which lead to buildUnshardedRequestsForAllShards with the expectation that this call will attach the UNSHARDED version to the collection. However, because [{{appendShardVersion}}|] doesn't modify its input parameter, they end up without the UNSHARDED version attached and appear to the shards as if they come from a direct connection.

This violates the sharding protocol and may lead to bugs that are hard to predict or diagnose.