Is there an expiration date for editing your posts?
The "modify" button disappears, from what i have been able to determine, after an approx. 18-24 hr period has elapsed, since the post was first placed.
Good powers of observation! It was set to 10 hours, inadvertently. I've disabled the limitation, so from now on, you can edit or delete a post at any time, so long as it's your own post.H