Champ-Select Timer Error

I'm being booted from lobbys while the timer still says I have over 10 seconds, for "Not selecting a champion". It has happened twice in a row now for Draft style (once ranked, once not when I tested the problem).

It resulted in the standard 5 minute ban from playing, then 15.
Speed test is clear, direct connection confirmed, no PvP disconnects. Reset client once, still occured.