Hello! I’m having the same issue. I’m on PHP 5.3.28 on Apache 2.2.x. Latest wordpress, with a commercial theme (firebricks). From an empty portfolio, based on Attachments plugin (latest release), i can add 12 images without problem when I save the page.
If I save it again, some random images are deleted. And so on, everytime I save, I got 1 or more images deleted.
Checking the source code of the theme seems fine.
Where can I check for getting more clues/details?
Thanks a lot!