Sorry for the slow response, @jscase.
(I’ve been updating some other features in the Tiller Labs add-on and finally had a chance to peek at this issue.)
First, it’s not intuitive but when you see a progress bar for more than 5 minutes it is likely the add-on has crashed. And when the add-on crashes, it cannot clear the progress bar. So, the add-on had probably long-since crashed when you closed it after two hours.
I saw a crash in the logs that may have been responsible for the issue you reported. I just published fix for that issue. Could you try the reconcile workflow again and let me know if it is working now? (It is possible it is yet another issue, but this is worth trying. We can dig deeper if the problem doesn’t resolve with the new build.)
Thanks for your patience,
Randy