SERVER-44422 made it so that findAndModify and delete (with limit=1) still work if the two phase protocol is disabled and only the partial shard key is given, as long as only one shard is targeted.

However, those changes have no effect on master because the two phase protocol will always be used if a partial shard key is given. This ticket should update the code for findAndModify and delete (with limit=1) to not use the two phase protocol if a partial shard key is given and only one shard is targeted.