I had this happen to me several days ago before the patch. Was "deliver baby" on your work task list? I feel like it has something to do with the pregnant sim problem.
I arrived to work on the first day as a medical specialist, three patients were already there but I had no walk ins all day. "Deliver baby" was on my to do list in the top left corner of the screen for the entire day, but no pregnant sim ever came to the hospital. In fact, I never had a pregnant sim show up in the next six or so work days that followed. Treatable patients would show up most days as they usually do when your sim is at work but not if "deliver baby" was on my to do list. If that task ever popped up on my task list, no more patients came to be treated that day.
This happened during my tournament challenge so I couldn't cheat to get a promotion. It was frustrating to say the least, but I don't think it's because of the patch if it was happening to me on Sunday/Monday.