SERVER-88391 added logic to the AsyncRequestsSender to return a failed response if it fails to "unyield" its session resources. The response will include only the failed status, not a shard id, which is the only case an ARS response won't have a shard id. This breaks an assumption in the batched write execution logic (e.g. insert, update, delete through mongos) that every ARS response has a shard id, which either triggers a dassert or a segmentation fault accessing a non-existent entry in a map.

We can either change the ARS to always return some shard id, or possibly relax users of the ARS's assumption that every response has a shard id.