I have tested this on three different browsers(Chrome, Firefox, & Edge) and on different platforms/devices.
It has the feeling of an affiliate links program (eBay Partner Networks, etc.) but I am not familiar with how those work.
I'm not saying that this is what is happening but..., I wouldn't mind if the forum is creating revenue to cover costs by being a part of an affiliate program. However, when links are broken and they don't get to the item that is being supplied as an answer to a question then the purpose of the forum is defeated. And, an affiliate program association, by the forum or a member, should be disclosed in my opinion.