Just as a quick note: Ever since Patch (I don't know if it has any influence on the bug itself or not), this glitch has been happening way more often. I don't know if that makes me the unluckiest person on earth, or if it has any influence over the frequency. In short, whenever I'm in a party, there's a slim chance for me to get thrown into a ghost party (AKA a party I made a few days ago), which essentially locks me and party members from EXP sharing and the map's loot. The problem is: This bug occurred to me five times yesterday, and four times today (two during important stuff which I couldn't be interrupted), whereas it had never happened during any of last week or the one before. Anyway, I think that's it. I can provide any details if needed, but that's all I can think of writing as of now. This is the only screenshot I took of the bug - As you can see, I'm grayed out (henro) with my main, which is illogically possible.
