On-call calendar does not have right-to-left language support, therefore if the on-call calendar is viewed in Hebrew language it will present in left-to-right format rather than right-to-left.

Install Hebrew language support and then view the on-call calendar while using Hebrew language.

No workaround available. On-call calendar uses 3rd party library: DHTMLX Scheduler which does not have right-to-left language support.