Tridion Experience Manager new Page error

Obligatory link to Stack Exchange

The TL;DR of the situation is this

I've got XPM in two environments. One has 2 XPM hotfixes. One does not.

When creating a page, the one without hotfixes:

  • Takes forever
  • Eventually shows an error that a duplicate page was created
  • No duplicate page was created (just the one in the CME)

The environment with hotfixes:

  • takes forever
  • only shows the loading icon
  • shows a "blocked loading mixed content" message in the browser console
  • shows the page as published in the CME

What does it take to get XPM to let me create a page, and then navigate me to the page that was created?

Or is that not a feature?