Maybe this has been defeatured, but it seems at some point the status of a running rule used to be displayed on the apps page, or on the rule it self. For example I have a rule that has a repeat until a condition is true. On the app page next to the rule it used to display something like "Repeating".
My rules still display this (in RM 5.1 for sure). Are you sure the rule in question is running? Try turning on logging in the rule if not certain to confirm it has started running and is repeating.