[Client] Disconnect Bug, not able to cast abilities?!

I got this bug 3 times now and only with my main champion Aurelion Sol. While ingame, suddenly the message "Trying to reconnect" appears and it fades after 2 seconds. At this point I'm not able to participate in the game anymore because I can't cast any abilities (the whole game). The game is kind of laggy, but I can still hear my characters sounds and I can move around (even when I'm lagging a bit). But I clearly can't interact with the Ingame enviroment (can't attack Minions or Champions). Suprisingly my internet is not the problem, it works fine. I even spoke the whole time with my friends via Teamspeak and there was no "connection problem" at all. Also worth mentioning is the fact that this bugs appears for apparently no reason, so it happend two times in the early game and one time after half an hour.

Pc restart or router restart doesn't fix the problem either. As soon as I join the game, it's the same like before: I can't cast my abilities and I can't interact with the ingame envioment. What really makes me think that this is a game bug has following reasons:

1. My internet works normaly
2. Restart of Client, Router, Pc doesn't fix anything (for me an indication of a server bug)
3. When the game is over, I can just search a new game and everything works perfect (that timing can't be concidence -> no connection problem)

I'm not an expert on these IT issues, but I think it's some kind of server synchronisation problem. Please try to take a look at this problem. Thanks!