Certain Friends falsly appearing as Offline

[Mr. Someguy]

Okay so this is a problem that's been going on for awhile now, and surprisingly hasn't been fixed. It was mentioned in a thread before, but that thread seems to have died since then. Basically, whenever you log into Steam, certain people may appear as offline to you when they are not, they will still appear as Online in Steam Community. They will be able to send messages, but you cannot send them back. Often times they have the [?] avatar as well. Getting them back is easy, resetting their status will fix it, but getting that message to them isn't, because you cannot talk to them when they appear offline.

This has been going on for months and mostly seems to effect certain people, though on rare occasions I've noticed it on others. Is this a known issue? Is there a fix for it? I've been waiting for one to come, but it's starting to seem unlikely that it'll happen.