This QA is currently listed as a "Featured" post, which thankfully led me here. Thank you for posting it.
Within the last few weeks, I noticed that Stack Exchange sites suddenly started having issues, sometimes presenting a message indicating that my connections were refused due to too much activity.
These often happened when volunteering my time performing reviews, with only one or two Stack Exchange browser tabs open. Although this made no sense, it wasn't a big deal because I could just stop performing reviews each time it happened. (It did get to be a big enough hassle that I noticed I was volunteering less of my time on Stack Exchange.)
The other times it happened was when I opened a bunch of Stack Exchange bookmarks at once. Although this second case makes some sense, I was logged in to Stack Exchange at the time, and so Stack Exchange could easily verify that I'm a long-time high-rep user (and moderator) in good standing, and therefore allow the connections to work as usual.
I don't know if my experiences are related to the new system being tested, but the timing is right.
I hope my feedback is helpful to Stack Exchange so that this system can be fine-tuned to provide an improved user experience.