If something similar has been asked/posted before then I'm terribly sorry but I'm unable to find any similar issues on Jira.
I have multiple stories in our Jira environment. At first I was using Google Chrome and noticed that when editing the "Description" of a story I was getting the last known version that I had edited for that particular story, even though a colleague of min had changed it in the meantime.
Switching to Safari resolved this issue and I decided not to pay any more attention to it.
However since today I'm experiencing a similar problem in Safari, on editing a new blank story it's being filled with the contents of the previous story I was working on...
Screenshot before editing the field

Screenshot when starting to edit the field

I've already cleared the browser cache etc. but none of this seems to be resolving the issue.
Hope the above makes sense and hopefully somebody has a solution.
Thanks in advance :-)