While preparing a test site for your investigations I ran into a more weird issue which may correlate:
when I include archived events to the event listing I get a MySQL error:
1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'order by dtstart , dtstarttime' at line 1
Please find the requested information in the respective fields. Since the event list is to short for paging, archived events would be necessary to include.
That worked with 4.2.7 but right after upgrading to 4.2.8 it does not but fails with the error above.