Actually I figured out where they pop up now!

If you want to speed up a "Wait for duration" action, go to System Scheduler > Scheduled Jobs > Today's Scheduled Jobs.

Add a filter of "Name = flow.fire" and "Script CONTAINS ______" (the sys_id of your flow execution).

If you change the "Next Action" date/time to the current date/time, it will then create the event that we used to see. Then if you update the "Process on" date/time on that event, then the flow will finally keep going!