Wrong calendar format in Appointment+

Hello,

I noticed the new version of Appointment+ has a drop-down calendar to help setting dates in the appointment admin panel.

Unluckly the drop-down calendar shows weeks starting from sunday, while in the wordpress general setting I clearly setup up the week starting from monday.

I think this is a bug, as the calendar does not read the global setting, but I need an urgent fix or a workaround.

Can you please help me ?

Thanks in advance

Antonio