Calendar widget no longer updates on iPadOS 15.1

I upgraded my iPad Mini 4 to iPadOS 15.1 yesterday, and I’ve encountered an oddity with the Calendar widget: it isn’t displaying anything! It seems to be stuck at the initial display with placeholder graphics. The Calendar app itself is working just fine and has all my calendars and subscriptions still in place. What’s even more baffling is that my iPhone SE, which is on iOS 15.1, doesn’t exhibit this problem. So I’m guessing it’s something specific to the Calendar widget on iPadOS 15.1. Has anyone else experienced this?

Update: this morning I awoke to find that the Calendar widget was now populated with events for coming day and next two days. I have no idea what changed during the night. Very strange, and doesn’t fill me with confidence for the reliability of i(Pad)OS 15.