Process failing and only saving some of the uploaded items.

Problem/Motivation

When doing bulk media uploads, I've found that often times if I upload, for example, 7 images, that only 4 are actually saved. This is true when doing the upload via /media/add or via the Media Library widget while editing a node. The AJAX upload process shows that all items are successfully uploaded (via the checkmark animation), but then the images shown are less than the original count (i.e. images are missing).

I do not experience this problem when using the Bulk Media Upload → module. And although that module doesn't allow you to edit media fields (e.g. alt text) when adding media via /media/add, it does allow you to do this when adding via the Media Library widget inside a piece of content.