Scenario:
0. shardB is the primary shard of "test" database.
1. test.foo is a sharded collection and has chunks in shardA [-inf, 0) & shardB [0, inf).
2. User sends batch insert [{-1}, {1}] to mongos, the insert will split up to shardA {-1} & shardB {1}.
3. test.foo gets dropped.
4. If user tries to send the same retryable write in step #2 to mongos, mongos will target the full batch [{-1}, {1}] to shardB. And this will result in the shardB applying the write {-1} and not {1}.