Looking up using Steam numerical ID works fine. Looking up using the ID in their vanity URL (not to be confused with their Steam display name) does not work for a subset of players. Instead it gives a 404 error, player not found. I suspect this has to do with whether or not they have been looked up using this recently, or something to that effect. I would suggest something like caching of vanity ID results from before, while not allowing new vanity ID lookups.
- Not working:
I would have put more links to make this easier for the reader to check, but as a new user I can only put two. So you’ll have to do the searches manually.
It has been like this for some time now. Several months at least. A couple of years wouldn’t surprise me either.