I can't create support tickets since I'm on the free plan, so...
Check out the modified dates in this page properties report. This is not a field in the properties macro. This is the system modified date. Note that they are all wrong, not just the two with impossible dates. I am in US. Date format should be YYYY-MM-DD. Today is 2024-03-08. I think the day is right on all of them. But those months... WTF.

Update: It's not just the macro. Actually appears it's not the report macro at all. This is the second page in the list:

And here is the page history from another affected page:

I did edit one of the pages as a test:
