Logged on and couldn't pick a game mode.

Had a red triangle with an exclamation point on it and when I hovered it, it said I was banned?

I panicked and started to try and find an email notification or anything as I didn't get an info card when I first logged in stating a reason for this. I decided to relog and try and find a Riot customer service rep to help me and when I logged back on it was suddenly fine.

I know I've had some chat restrictions for being toxic but I've been actively muting all of my teammates and have All Chat turned off; as far as I knew I hadn't done anything in my last few games. So I can only assume this was some kind of client bug?