Not sure if this is a totally new issue but I’m not seeing anyone else that’s posted this situation yet. I only play solo and have never partied and my account reset. Here is my story, hope it helps others.
So my account reset and I do play solo. My wife happened to be using the Xbox and decided to start the game up for me and accidentally used her profile instead of mine. This caused the game to start up the tutorials etc. I ended up then backing out of the game so i could log in as myself and bam I was back at lvl 1, but hey all my leaderboard stats are still there. So yeah solo is not safe either.