The page switch fuckery I'm noticing is not quite as severe as what you described, but still annoying:

* say you're on page A, an open pull request

* merge the pull request

* switch to a different site entirely

* go back to github's page A

* notice how it shows the pull request as if it wasn't merged yet

* refresh the page and see the status switch to merged

I'm using Firefox and I've never tried reproducing this on Chromium.