$currentOp output for multi-document transactions used to display the actual readConcern being used. In some cases this could lead to intermittent instances of an operation displaying a different readConcern than the user-provided due to internal operations that temporarily changed it.

With the merged ticket, $currentOp will now display the user-provided readConcern without the possibility of intermittent changes.

Description of Linked Ticket

There is a harmless race between a thread performing an operation using DBDirectClient that temporarily resets the ReadConcernArgs (example) and the currentOps method reading the ReadConcernArgs of the target operation (code).

The main risk potential for this is an operation printing potentially wrong information for the read concern used. This would occur if the currentOp thread acquired a copy of the data while the temporary reset was happening.