I have a spreadsheet that has cells with two currencies. Numbers does not let me manually change the currencies: When I click "Cell" -> Data Format -> "Currency" and chose a different currency, it reverts back to the currency it thinks is needed. 

The problem is new since Version 4.3 (5046). My spreadsheet worked flawlessly until now. 

As a consequence many of my formulas are broken now since Numbers refuses to add different currencies - so this is not just cosmetic.

Thanks for your help!