The timeseries insert path checks for the presence of the bucket collection before acquiring the collection and checking the shard version. This is because the timeseries bucket options are needed for inserting into the in memory bucket catalog, but the collection locks are not needed at this point (because nothing persisted is being done yet).

In the case that a moveCollection happened, the bucket collection may no longer exist and so we will return NamespaceNotFound at the first check rather than throwing staleConfig at the later check.