Sporadic rate limiting on VRM

Occasionally I find that when I’m in the middle of looking at data on VRM, especially when switching between sites and changing the display data range (for example switching from Today to Last hour), I am inexplicably stopped in my tracks by an error telling me I have sent too many requests.

It doesn’t appear to be particularly consistent - I had it occur a few minutes ago, but now when trying to simulate it by doing the exact same thing (switching between my 3 sites, going to each site’s advanced page and changing the display data range), it did not occur again.

I don’t feel as if I am applying too much strain on the system; I really am not sending that many requests at all, so I find this sporadic rate limiting rather strange.

Is this something that is known and being looked at, or is it currently the expected behavior?