First of all I don't know exactly if there was a thread for this issue, but since it been a known bug for a very long time I think it requires a refresh.
Fix the friend list randomly removing people one sided/both sides.
My friends wouldn't get any invites from me making me think that the invites are broken or that game is having issues, just to realize that it wasn't that they weren't getting any invites from me because they weren't in my friend list anymore.
I have 501 friends currently and every time I add more people I am pretty sure someone else from my friend list gets automatically randomly removed, sometimes the other party will still see me as yellow (friend) but for me they won't show up on my friend list and they would become whatever rank they are, re adding them back from the website or the api does NOT fix it, always I have to be on the same instance as them and re-add them in game.
Sometimes it's the exact opposite where they see me purple but I see them yellow, so the both parties have sometimes to remove each other and re add, and here comes the worst part, give it a day or two and when we see each other again it happens again and again, I personally had to re add someone over 5 times, for the past week, now I am literally playing the lets check my friend list if they are gone.
And recently another annoying thing is, when someone gets removed like that if they changed their names even once and I try to search them up on the website (or in game) to check if they are friends still or not, even if I use their current name or old name their profile won't show up at all making it impossible to even check if I still have them added or to try to add them back.