Not sure if there are other calendars in the system, but I guess it's the same everywhere. Just to be clear, the first day of the month (number 1), should be where number 7 is right now. number 2 where number 6, etc`. Days titles are also reversed, so where the letter ש is right now (top right, below the right arrow), it should be א (below the top left arrow) and so on.
In addition, pressing the arrow to the left, should present the next month to the user (in RTL), but it gives the previous month, so I think it's related. Moreover (not sure if it's a bug/suggestion/related), when pressing "cancel" on the banning window without choosing a day in the calendar, the calendar window stays on top of the previous screen.