I have the same issue. If you block time at the end of the day in the calendar, the last time slot still shows as available when a user books from the booking page.
I wish I could post a screenshot. But for example, if I block 4pm-7pm and save the changes, go to another day, then come back to that day, 4pm-6pm are blocked but the 7pm slot is now available. And of course, if a user goes to the booking form, 4pm-6pm is not available to book, but the 7pm slot is available. Even if I separately block the 7pm slot, it will not save.
It would also be great to block a series of dates. For example, in calendar view, highlight multiple days, then select a time range to block. Currently, especially with the problem mentioned above, I have to create a holiday for every time range I want blocked.
Thank you!