When we unfreeze a conncheck, we must make sure the timer will keep running. The conncheck gets unfrozen from state FROZEN to WAITING. If there are no other IN_PROGRESS connchecks, then the timer will stop and the WAITING conncheck will never go into IN_PROGRESS state. This can cause a lock because the state of the stream will be never be READY/FAILED as there will be one conncheck in WAITING state remaining