Similar to SERVER-45934, since DBClientCursor APIs are not thread safe, calling DBClientCursor::more concurrently in two different threads can race in setting private members. In particular, one thread can set cursorId to 0 during dataReceived while the other thread checking the cursorId in more(). Thus, in CurrentOpExhaustCursorTest, runOneGetMore can race with the startExhaustQuery thread on calling more(), resulting in false positive failures.