Consider the following sequence:

1. a shardCollection request for an existing TS collection is received by the command handler; the request does not include any TS options (the current ones have to be maintained)
2. the request is dispatched to a new or existing Coordinator (running on a separate executor) through the getOrCreate() method
3. the command handler thread is suspended
4. the DDL Coordinator thread advances its execution until the translateRequestParameters(), which modifies its _request field by appending the TS options for the targeted nss retrieved from the local catalog
5. the command handler thread is resumed; to verify that getOrCreate() did serve the ongoing request, it invokes the checkIfOptionsConflict() method specifying the original request parameters; due to what happened on step 4, the check fails.