form submissions report a warning/error related to form tokens

I had a jira task description webpage open for a while (probably more than one hour) and then entered a comment to the task, which resulted in a warning / error complaining about a form token that has expired. This hasn't prevented me from posting a comment - I had to click "repeat action" (even though it notifies that if I had attachments, then they are lost).

This is really annoying since it doesn't actually stop me from commenting on tasks, but still requires an additional action without any meaningful description of what has actually happened and why it is important.

In the warning there was a link to a document describing how to disable that token checking: http://confluence.atlassian.com/display/JIRA/Disabling+Form+Token+Checking?clicked=jirahelp