I just cleaned up my site with this process:
1) removed any orphaned events (about 10 disappeared) – at this point I had 3 left.
2) Permanently deleted 2 thrash events
3) Modified one draft event with a bad date (1/1/1970)
All 3 gone.
During the process I also did the following (that didn’t help):
Delete all old bookings (about 6-8 – only used when testing it)
Checked for recurring events (we don’t use recurring events since it doesn’t go well with polylang) – nothing there.
I hope this helps anyone out there…
