If you have a credit card which includes Priority Pass with no charge for some number of guests, this does not mean that the lounge or restaurant is not compensated. It means that Priority Pass or the sponsoring credit card absorbs the Guest fees.

In this example the card issuer removed the Guest fees from olguita's husband's credit card account. The issuer may have absorbed this cost, or it may have disputed the accuracy of the Guest charges with Priority Pass. I doubt the consumer has a way to know.

When you use Priority Pass, the restaurant reports a Visit + Guests the same as a lounge. They receive a flat amount person from Priority Pass, and they deduct a flat amount per person from the bill. In this example the restaurant apparently reported more Guests than were served.