"Add Friend" Links Not Working

[what the bruh]

Hello all! I've had a curious issue with links to add people as friends from third-party sites not working properly.

I do a lot of trading on third-party sites, and I used to use a feature where I could click on a link that would prompt to open up in steam, instantly send a friend request, and allow us to start communicating. Links like:

steam://friends/add/11111111111111111

But for a while now these links have stopped working! Regardless of who I'm trying to add, all links of this kind take me to the main "Friends" page. I've tried clearing browser settings and using different ones and reinstalling Steam.

It's not a big issue, I just miss the convenience of it all. I post on the off-chance that some angle out there knows how to help me restore this functionality.

Cheers!