Once again Major Geeks is not allowing me to post on my own thread tonight.

This time it says "Your submission could not be processed because the token has expired.

Please push the back button and reload the previous window."

Token?

See screenshot.

 

Have you read this? https://support.mozilla.org/en-US/questions/931157

 

If the Ctrl+F5 solution in the support forum thread that evilfantasy linked to works, then it's a browser cache issue.

Your attached image shows Memory: 93% but does not indicate if that is percentage used or percentage free.
If that is percentage of memory Used, then you might have a limited cache size affecting that.

Other than simply using Ctrl+F5, the only remedy I found is to change the check_doc_frequency value to 1.
The default setting is 3.
That still may not fix the refresh issue and it is a global setting, so you can not set it for just certain web sites.

[noparse]http://kb.mozillazine.org/Firefox_:_FAQs_:_About:config_Entries#Browser.[/noparse]

http://kb.mozillazine.org/Browser.cache.check_doc_frequency

 

I've had this issue a couple of times because I walked away from the computer during the middle of a post before submitting it. I went back as requested and clicked on the rounded arrow in/near the address bar. The page refreshed and I was able to submit my post.

 

I use Pale Moon and I don't think I've got that unless the post has been waiting for 8-12 hours or more (I have a feeling that 18-24+ hours might be the trigger zone, never checked the timing) - it may also depend on server-side factors, like other replies being added, making your current browser content 'stale'.

Related to the memory issue brought up by mjnc but probably unrelated to this problem; by default, Firefox has a stupidly wasteful HDD cache size of 1GB for stored web page files; Pale Moon limits this to ~350MB (Alt > Tools > Options > Advanced > Network > Override automatic cache management - check the box and try a number from 200-400 (mine is 250MB, maybe that's the current Pale Moon setting?).