I have cards that repeat on the 1st of every month. I also run a rule that, when new cards are added to the To Do list, the due date is set to the last day of the month. However, the cards always set the due date to the 1st of the month.
Rule:
When a card is added to the list "MY TO DO LIST", set due date on the last day of this month
I've just run another test, and it's definitely a bug.
I have checked the location and time zones, and these are correct.