EdgeRank is getting tweaked regularly. On top of that they improve their link crawlings alot, I noticed just 2 weeks ago a major update I used to cloak my affiliate links.
You cannot use html meta refresh to redirect to affiliate link, facebook uses a javascript crawling bot so it's gonna catch that one too
You cannot use JavaScript redirect, again, their crawling bot will follow the redirects
You cannot use PHP redirects with header because everyone one of Facebooks 5 different crawling bots will detect this
Considering the huge amount of users, posts and interactions each day on facebook, every link tag is done on feedback from 1. crawling system and 2. user feedback. The more users mark it as spam or hide it, the lower the reach. They also use a system to detect content in your OG meta data to see if it matches anything malicious from their database, and dramatically reducing the reach of that link if it's found.
My best tip to you is to use a complete prelander with user interaction before you redirect your visitors to an affiliate link. Or you can use a cloaker like you can find in the marketplace but they base it on Useragent + IP ASN (if an IP belongs to Facebook, then hide the true intent)
https://ipinfo.io/AS32934#blocks
https://ipinfo.io/AS54115#blocks