If you manually schedule a recording crossing midnight to auto-repeat each weekday it will cause problems at the weekend.
For example: scheduled from 23:30 Thursday to 00:30 Friday. When it re-schedules a day later it says ‘start at 23:30 Friday, OK. Finish at 00:30 is not OK as Saturday is not a weekday. So I’ll set it up as 00:30 on Monday.’
This fills up the drive rather faster than expected.
I’m sure we can’t do anything about it but I don’t recall seeing it mentioned elsewhere.