Product not saving, and then erasing content

Hi all,
I’ve had this new issue popping up.
I edited some products, and while replacing an image (.jpg, 1080px. less than 100kb), I could not save (see screenshot). The SAVE button is blocked, but after about 30 sec, it allows me to save again. However, when I opened the product again, all additional pictures were erased and all my description!?!
Has anyone see this?

Here is my site Read-Only: LINK
(how to share your site Read-Only link)