If any 1 report completion time passes the 15 min interval, any subsequent reports scheduled in that same interval will be skipped.
E.g.
Report A, B, C & D are all scheduled @ 12:00am to be run
Report E is scheduled to run @ 1:00am
Report A started to run @ 12:02am, completed @ 12:03am
Report B started to run @ 12:04am, completed @ 12:16am
Report C and D will be skipped.
Workaround: Schedule the report to run at a different 15 min interval with Report Shift assigned.
This will be resolved in a future release.
Related Case:
00145867