It is a known issue that during scheduling, if the calendar has the "To" time as 24:00:00 in the calculation rule (transaction /sapapo/calendar for calendar ZKAL), then the times are scheduled at midnight on Friday. This is because Friday at 24:00:00 is the same as Saturday 00:00:00. To correct this,you can change the calendar on Friday "to" time to 23:59:59.
If the above recommendation does not solve the issue:
There is a known limitation within the scheduling framework. A work around for this is an implementation of the BAdI /SCA/SCHEDULE. If you implement the following code in the method 'MODIFY_INPUT' the scheduling will work correctly for the calendar configuration maintained.
FIELD-SYMBOLS: <fs_request> TYPE /scmb/sc_request.
LOOP AT ct_requests ASSIGNING <fs_request>.
IF <fs_request>-entrydate-actitype = 'GR' AND
<fs_request>-entrydate-dcat = 'B'.
<fs_request>-entrydate-time = <fs_request>-entrydate-time + 1.
ENDIF.
ENDLOOP.