Unknown price discount for registred users

[hwit]

Hello all, I am struggling with my Prestashop 1.7.8.6 eShop settings.

I have global eShop discount for all products, 10%. This discount was set thru Catalog/ Price Rules/ Catalog Price Rules. It works as expected, BUT, if user registers on our shop, on one exact category, user will get another discount, which I do not know about and dont remember to set anything. There is no other discount than described above, also, there is no discount rule at Shop Parameters/ User Settings. Also checked product settings, but there was no other price or discount shown. If I am in backoffice, prices are shown correctly. Problem occurs only at product page for signed up users in one concrete category...

Any help ?

Also giving screenshot for demonstration...

Thank you all.

Correct picture shows price as desired, works only for unregistred users

Incorrect - I dont know from where prestashop is getting that price...

There is no other tax than standard 20% tax rate, and also 20% from 21.90 is 18.25, so it does not correspond with price for signed up users which is 17.52 instead of 21.90, at this exact product.

[ComGrafPL]

Prices are different, so you need to have some default discount for registered customers + ( -10% ).