Hello.
I think (I may be wrong).
When I set the VAT (via istraxx eu vat checker) to 0% the invoice is send to me with VAT -100% why is -100% not 0% as it is set on product (everything is configured well, VAT rates are ok except this one 0%), even tax rate on shipping method is calculated ok to 0% (when is needed of course) but on product hmm... not
example on picture
tested for 0% and any other VAT rate

Topic to delete.
there was a little problem with publicate vat tax rule 0%.
I was sure that it was publicated (it was showing in product settings etc.), finaly I found that somehow this calculate rule was NOT PUBLICATED. My stupidity, sorry.
Ewerything is fine for now :)