[SalesForce] Remoting request invalid for your session error for just one machine

Recently I have found out one problem in JS remoting in salesforce is that It doesnot work with the Enter key. For eg. If you hit any key apart from enter My JS script is calling. On every Event it is working but when I it enter it does not work. Then to verify the same I have put if statements to catch the key value == 13(Enter key Ascii code) to verify if it is Enter key issue only.

TO my observation I am correct the issue persists with enter keyevent. Normally JS remoting will listen until the response is returned from the apex class. But on hitting enter key it escapes every thing and just executes the complete code and exit. It will not at all listen for the response. Infact I have seen in the logs with enter key it is skipping the JS remoting call.

Please check if same is the case with your event your are trying.

I was able to replicate this issue, very interesting one. I'm not too sure why exactly you are getting this error. However you should save your case in your controller before to call your second page, that works for me :

public PageReference nextPage() {
        update c;
        Attachment att = New Attachment(Name = 'Test.pdf');
        att.parentId = c.Id;
        PageReference page = new PageReference('/apex/Case2?id=' + c.Id);
        att.Body = page.getContentAsPDF();
        insert att;
        return new PageReference('/' + att.Id);
    }