It appears as if the window for editing a post closes when you leave the thread, but often, you think of something to add to a post a few minutes later, so it would seem reasonable to allow people to edit their postings up to maybe an hour or so.
The issue is that I often don't do anything until I go back to the thread later; like today, barely 4 hr later and realized that I responded with an empty post and there's no way to delete it.
I think the window to delete or edit should be 24 hr.
We had a look at this and everything appeared code-wise fine but clearly not. There have been other users reporting this periodically. Post edit is currently set to 12 hours so it shouldn't be an issue. Likely a time zone issue somewhere in code. I will investigate.