The issue of tax rate is of secondary importance. If general conditions are met and the expense was related to taxable business, the buyer of the good or service may deduct VAT. This is confirmed by the latest interpretation of the director of the National Treasury Information. However, the case law shows the opposite conclusion. An in-depth commentary by Małgorzata Militz, an expert on VAT, can be found in the article at Prawo.pl.
The article is available at the following link: https://www.prawo.pl/podatki/bledna-zanizona-zawyzona-stawka-na-fakturze-a-prawo-do,497911.html