Steps to reproduce:
1) Set usedaysmode to either push the due date or don't fine based on the calendar.
2) attempt to check out an hourly circ item
3) you should receive a pop-up asking for a date due since the due date is about to be in the past.
4) after agreeing to checkout, you item is now overdue since it was due at 00:00 the day you checked it out
I can provide screenshots if needed to illustrate the problem.
This worked in 3.8.3 but is broken in 3.8.4 and 3.8.5, I believe.
Created attachment 12889 [details]
screenshot of pop-up asking for date due
Here's a screenshot of what happens when you try to check out an hourly item. As Elliott said, you get a pop-up asking you to confirm the due date. The pop-up has a blank due date box. If you click on Yes, it gives a due date of today 00:00, which means your item is instantly overdue, instead of giving a due date of one hour from now (or whatever your hourly circ rule says).
As a result, you can't circulate hourly.
Created attachment 13444 [details] [review]
Bug 8882 - Hourly circ doesn't work with the calendar
I should note that this is fixed in both 3.8.x and master. So this bug report should probably be marked as RESOLVED / FIXED.
*** Bug 9041 has been marked as a duplicate of this bug. ***