Event Dates Randomly Changing

Ever since the 6.5.1 update (at least that’s when I noticed it) I’m having a weird issue where the dates of the events change… sort of?

In the events list in the WP admin, I have many Draft events that I imported from another site with the WP importer, plus 4 published events that I added new. All of a sudden I noticed that event though the list was showing the 4 events while set on “Future events” in the filter, the dates were all dates from the past. Eventually I found that if I use the “Quick Edit” link to change the category, it also fixed the date, and then I found that if I open Quick Edit and save it without changing anything, it also fixes the date. But weirdly then a bunch of events in the Drafts end up with the wrong dates. If I bulk-edit all the drafts and again save without changing anything, it fixes the dates in the drafts but messes up the dates of the published ones again.

I’ve deactivated all the relevant plugins and it’s still happening and I truly cannot imagine what is going on. My only recourse, seemingly, will be to delete all the past events and hope the new events keep their dates after that.

I can’t figure out how this happened but what I did was:

• Imported all events from another site using the default wordpress importer tool.
• Added 4 new events on the new site.
• Everything worked fine until I updated to 6.5.1 (or maybe 6.5?)
• Use Quick Edit option to change event categories.
• Observe that other events randomly change their dates.

I’m wondering if there’s some issue with the Event ID getting confused with the events I imported? Maybe some of them accidentally have the same ID?