Final Price is 0 when Specific Price is applied to only 1 combination

[Dobre Ceny]

Hello All,

 

I have strange issue with my shop.

 

In order to avoid complicated calculations, I've set default price of my product to 0, then I've added some combinations (different sizes) with price impact (rise) on each. The next thing I wanted to do is adding discount on specific combination only - and BAM! The final price of the product with this specific combination is 0. First funny thing - on the front-end product page price is OK. Second funny thing - when I add same discount on all combinations price also is OK.

 

I've already tried switching theme, disabling filter modules, clearing cache - no luck this far. Does anyone have any suggestion how to fix this? Using PrestaShop 1.6.1.4.