The custom links crated with WC Affiliate are taking more time to load because of a caching issue. If you’re using a caching plugin that caches the static content of the pages but doesn’t do when the URL contains query strings added. Query strings are pairs of keys and values that are added to the main URL. In our case, ref=10 is an example of query strings.
This is why it loads faster if you access a clean URL (without any query strings). Example: codexpert.io/wc-affiliate but takes more time when codexpert.io/wc-affiliate/?ref=10&campaign=test is accessed.
The same happens if you test with any query strings even that are not related to WC Affiliate. For example: codexpert.io/wc-affiliate/?mykey=myvalue
So, as you can understand, the problem is not related to our plugin. Please reach out to the cache plugin support and see if they can assist on how to enable cache for URLs with a query string.