Not "Ready" Button in Team Builder

it was the strangest but I have seen. We had a full team. Heimerdinger was stuck on "Setting Up." Talon was stuck on Ready, shortly after, Lee Sin hit ready after I tried to look for the button. I thought for a moment that I was stupid and that I was too blind to see the button.

Lee Sin later left, Talon was stuck on Ready still even though we had 4 people only. Yi, the new guy who replaced Lee Sin, was able to hit ready easily.

I'm just letting you guys know that this bug does exist. And I would also like to know if anything else has experienced this bug. Thank you and have a nice day! <3