Setup: 2 mongos, 1 shard

1. Enable sharding on test db ysing mongos A.
2. Use mongos B to perform a query against test db.
3. Use mongos A to drop test db.
4. Trying to enable sharding with mongos B gives the result:

{ "ok" : 0, "errmsg" : "already enabled" }

Current workaround is to force mongos B to refresh it's config with

Also attaching script demonstrating the behavior (stale_db.js).