Sudden game reinstallation while queuing

I was just queuing for a TFT ranked game (before hitting on "accept" button luckily), then the error log spawned asking ke to send report, then the game window closed, asked to me permission to install the game and started installing league of legends.

No need to mention the game is installed from months and updated correctly since last patch (yesterday).

Small extra: installation is taking me about 1 hour, but it's funny to read it thinks it would need more than a day to complete.