There is a race condition in the Wait for Condition action that occurs if the record to be watched is updated in another thread or node after the flow checks it and before it quiesces with the record watcher. When this happens the flow will be 'stuck' waiting for the record to match the condition it is already in.
Steps to Reproduce
Flow Designer flow hangs because a "Wait for condition" steps is stuck in waiting state even though condition is met for that step
Updating the record the flow is waiting on will push the flow forward.
Related Problem: PRB1343070