I have a redirect script on my site which sends visitors to an affiliate site. However in the last month I've noticed that Google webmaster tools is reporting my outbound links as a 404 error. Here is the breakdown on how its setup:

My outbound links are coded like this:

<a href="/f/c123" rel="nofollow" target="_blank">Link Title</a>

My redirect script will then perform a 302 redirect to the affiliate link

Originally I had the affiliate links (CJ) directly in the HTML, however I noticed over time that this had some impact on my sites traffic. So I changed them to a redirect script and my traffic returned. This seemed to work with no issues for over 1 year but now I'm getting soft 404 errors in Google webmaster tools.

I did try adding a rule in my robots.txt to block any links starting with /f/ but I'm not sure if this will help or Google will still report soft 404 errors.

I am considering as possible options to change the a tag to a button tag and use an onclick event to load the link.