LOL client causes DNS issues

I have reported this multiple times, but RIOT's support continues to explain this is "my computer's fault" - I play every other online game I want, hours and hours straight, never do I have any internet or connection issues. ONLY with LOL and also ONLY during champ select (never during an actual game), frequently, my internet is disconnected and my computer experiences DNS problems for about 1-3 minutes.

This is MORE LIKELY to happen if I use the chat during champ select, and even more likely to happen if I go to rune / mastery pages. If I do absolutely nothing, the problem does not occur.

But hey, I guess it's "my computer's fault", right? Why don't you point me to the Hextech Repair Tool?