Yes I have noticed the exact same thing on Reddit lately. My guess it's because they started sending "Cache-Control: no-cache" which prevents Firefox to cache the page for the back button.
Re:Firefox 39.0 released
by paralelogram on Friday July 03, 2015 @04:31PM
(#9827779)
Ah yeah that makes sense, I thought it might have been something to do with their recent switch to HTTPS only.
Re:Firefox 39.0 released
by ElongatedTowel on Friday July 03, 2015 @11:39AM
(#9826149)
I haven't seen many people mentioning this problem before. I've seen it come up in discussions on the current AMD GPU lines. Hard to say who is to blame, but it's rarely obvious just how many problems there are before buying a card. I got a cheap R7 260x which seems to have trouble with waking up from low power states. Some people even made custom BIOS's to fight the problem.
I don't know how more modern stuff like accelerated transforms, canvas, WebGL or DirectWrite play into that equation. Browsing seems to pull out GPU's from the lowest power modes constantly, which might cause these problems on a wide variety of GPUs.
Can you post a screenshot?
Sure here you go http://i.imgur.com/RNXdLI0.png
Just tried in Nightly and looks like the bug is fixed?
That's possible. It looks like https://bugzilla.mozilla.org/show_bug.cgi?id=1160070
Also has anyone else noticed that Firefox is no longer keeping the page state when navigating back? For example on Reddit go to the comments section, minimize a few comments then navigate to a link then go back and none of the minimized comments remain minimized, in Firefox prior to 38 things worked correctly.