Problem is that if you create a shared schedule with 'Monthly' repeat and set 'Last' Wednesday, then it saves with 'First', 'Third' instead of 'Last'.
Steps to duplicate issue:
Known issue. Issues between scheduling v1 vs v2 API used in Shared Schedules.
ITMS 8.5, 8.5 RU1, 8.5 RU2
This issue has been reported to the Symantec Development team. A fix has been added to ITMS 8.5 RU3 release.
As a workaround, please perform the steps below:
224511 "Cannot create or edit shared schedules"