What you’re describing sounds like a packet loss issue, which causes the disconnect. As for the summer games update, it could be coincidence. Most of the threads on the forum (I normally post in Tech Support) are issues on ISPs or home networks, and usually not Blizzard unless they have a major outage, which they report. Follow the tips in this thread:
And then if you’re still having problems, make a new thread in the Tech Support forum with WinMTR results for us to look at.