For one specific On-Call schedule, it's showing Secondary on-call above Primary on-call causing confusion.
Roster records have the same Order set.
The behavior seen is related to the values set in the Order field on the roster records. This can be seen in the Shift (cmn_rota) record in the 'Rosters' related list. The Order value set for both Primary and Secondary is '1'. This is not configured properly, each roster should have a different Order value. Simply updating the Roster order to a value of '2' for the Secondary roster will resolve the behavior.