Sync from MS exchange calendar to Google calendar in iPhone calendar app iOS 17.1.2 quit, now only showing 1 day 1 month ago

Realized yesterday morning, Dec. 9, that MS Exchange calendar events from a university account that were shared to my Google calendar in my iPhone calendar app were no longer showing. This calendar sharing has never worked on my desktop browser calendar or in the Google calendar app, but it has worked for years on the iPhone calendar app.

Things that did not work: re-sharing the calendar with the .ics calendar link, restarting phone, deleting old calendar and re-sharing on the phone, re-sharing in a browser.

I happened to notice when re-sharing on the iPhone that I was getting a preview of a calendar event on Nov. 9 - and only that event. I realized with the re-shared calendar, every time I would re-share, it would only give me a calendar event on a single day, one month prior. Today, Dec. 10, I can no longer see the Nov. 9 event, but I can now see an event on Nov. 10.

In the metadata attachment sent with the calendar sharing link, it appears to be coming from MS Exchange 2008.

Not sure if help can be found on this forum, or if I need to try to chase something down on Microsoft or Google forums. I'm posting here because I wondered if perhaps the last iOS update had scrambled something.

Any help to get me pointed in the right direction among the software behemoths would be greatly appreciated.