Credit note is adding up incorrectly

I added an credit note by cloning an invoice and setting the amount to negative but then the total doesn;'t include the VAT.
It says:
Item -125 x 12 VAT 21% -1500

Of course it should say -1850 (as in this case it’s a total refund)
What is happening here?

regards, Michiel

Do you have inclusive taxes enabled on Settings > Tax Rates?

Hi Hillel, Thanks for the quick reply!
I see that it says: “Note: Inclusive taxes are not enabled.” but I don’t see an option to change that.
I now tried the option " Enable specifying an invoice tax" and then tried the same invoice and I got the correct total (1850). I then turned this same option off again and it still worked correctly. So I seem to have solved it, but no reason why.
thnx, Michiel

It seems that somehow a payment was made of the missing -315, but we cannot figure it out how this has happened. For now this is fixed.