This scenario is a special type of purchase that does not generate any “download key”, so it will not appear in your library as an owned product.
Is this only concerning the appearance in the library, or is the faq misleading here?
I verbatim quoted the faq and highlighted the relevant portion. "If someone pays for a project, they are granted ownership to it". That was in the section of 0/donate projects. Followed later by "This is important to be aware of if you decide to convert your project to Paid at a later time."
Also, the faq talks about ownership in both cases, paid above minimum paid price and donated to a free game, so the distinguishing factor is not ownership. English is not my native language, ownerships sounds wrong to begin with, but I guess it stems from an older term like owning a copy.
And because it cannot be the distinguishing factor, with the faq in mind, I assumed games are just sorted in purchases/donations according to their current status of paid or free.
Or they simply get written in a list on the customer's account and that status does not get updated. Which I assume now, based on your reply.