Dozens of entries into Media Library for one image upload since 4.0.

Hi,

I’ve updated to 4.0. and everything worked fine until I tried uploading a new image. Normally it takes a while to upload an image, but this time it took really long and after a while I got an error that the upload had failed. This happened three or four times.
Then the upload succeeded, but in the media library I saw that there were dozens on entries for that one upload. It skyrocketed my cpu usage on my host’s server and even caused my blog (https://wonderfulwanderings.com) to be blocked for a while.

I’ve made a screenshot of what the files look like in the media library but don’t see a way to attach it here and I have nowhere I can put it online.

Another thing I’ve noticed is that there are now also these kind of entries for images that had been uploaded prior to the update.
With “these kind of entries” I mean that I don’t see an image but some kind of folder and the details only contain the file name, but no set title, alt text or description.

I will refrain from uploading any images at the moment as I’m afraid of having my site blocked again.

Some more info:
I’m on 4.0.
Theme: Weaver II pro
Host: HostGator

Thank you for looking into this.