I have 3 social media icons: Twitter, facebook, linkedin. The facebook and linkedin url is messy
I have create subdomains forwards to the urls

When I add linkedin.mysite.com & facebook.mysite.com into the site's profile. They become www.linkedin.com and www.facebook.com

I feel like this is a bug than a feature/support request. If I type bobisyourunclue.com into the linkedin spot it should still work.
Maybe typing in a non-social media link, you receive a warning, but not an error message.