I enabled the Debug Menu setting, "disable back/forward cache," and so far so good. I was able to renable the troublesome extension with no reloading issues so far. You may want to try it. If you can't see the Debug menu, here are instructions on how to enable it:
How to Enable Safari’s Hidden Debug Menu
- Quit Safari
- Launch the Terminal and enter the following defaults write command:
defaults write com.apple.Safari IncludeInternalDebugMenu 1
Relaunch Safari
The “Debug” menu will be visible to the far right in Safari’s menubar choices. If you want to disable the menu, go back to the Terminal and type:
defaults write com.apple.Safari IncludeInternalDebugMenu 0
Another option worth exploring may be the NoPageCache extension:
http://canisbos.com/nopagecache