Group Disbanded in solo ranked?

June 17, I played a ranked game and was in champ select for a ranked game and before it even launched, I got kicked back to the main menu saying my group had been disbanded and no reconnect option. Didn't think anything of it so I went to sleep for the night and when I logged back on the next morning, it gave me a warning from leaverbuster. Not sure what to make of something so unexplicably random.