Priority Groups not working

Thanks for the quick reply. In the pool in question, it's set to 10 seconds. I did see an article about slow ramp time, but it spoke of a fix in post BigIP 11. I'm running 11.4.1. It's odd, because initial testing with one client showed no shift back, so I was under the impression that it was the cookie persistence in play, so I arranged a test with a few clients and still the same. Even clearing browser cache doesn't have an impact. The only way to get traffic back onto the higher priority nodes is to force the others offline.