It's reasonable to suppose that the same libraries are used in all versions of the Utility. So if the bug exists in U3, Canon should be aware and duly post a fix. If you're not experiencing severe network problems, I wouldn't worry about it. I mean...
I didn't get as far as wireshark, but I did get as far as tearing my hair out. I'm going to open a support ticket with Canon. I don't hold out a lot of hope, but I know from another forum they've already heard from at least one person about this pa...
I'm experiencing the same problem. EOS Utility 2 brings this gremiln to the party. Only found out by selectively killing processes that the Canon UPNP detector was responsible for bringing my network to its knees! Not impressed.