Adding Media images to existing gallery replaces previously added images.

Problem/Motivation

Adding Media images to existing gallery replaces previously added images.

Steps to reproduce

• Add a new image gallery to your node.
• Select some images using Media Library
• Now you want to add some more images.
• Again select some images using Media Library
• Notice that the images added first are now replaced by the last added image(s)

Proposed resolution

Uploading a new image instead gets added correctly to the gallery, and also creates a new media entity.
There are no notices in the browser's console log.

Remaining tasks

Write a patch?