Sounds to me like the old daylight savings time bug may have reared it’s ugly head.
I’m not sure this was ever resolved. We went through our system and made sure we didn’t have any reports in our Business Objects system scheduled to run between 2:00 am and 3:00 am and we haven’t had any problems since then.
Almost certainly a DST issue. See my post here from 2016; we were on BI4.1 SP06 at the time and had a similar issue. No issues this year on BI4.2 SP04.