I've been searching for matches in Mayhem for the last 10 minutes. It finds every session out there, makes teams, and then restarts search. I've never had this problem go on past 1 session found.
Happening to me too on Xbox with seemingly all gametypes. Tried to search Halo 2/A + 3 BTB and it'd find a team, then restart. Backed out and tried ranked H3 Team Slayer and found a few games pretty quickly. After I won the second game, it immediately backed me out without showing the XP earned and would automatically back out of the search anytime I tried after that. Very frustrating.
Now i find games, but at the end of each one it says your game session has been interrupted? I cant tell if im getting exp or not because it just skips past that part. Even if i am and its not showing it, i want to see it to know my exp gain for teamwork.
After the never ending search, i then went to forge and looked through some of my maps. Then it fixed itself. Hopefully, that's the only time it happens. Thank you all for confirming that it wasn't just my net acting up :)