Preconditions:

Video CI created for example in Media/Multimedia

Steps:

1. Go to Page and click button
2. Choose Landing Page
3. Choose default layout and confirm
4. Drag and drop video block and attached there a video from preconditions
5. Grab another block and try to place it above the video block but don't let it go, put it back after a while - see attachment, please

Actual result:

A lot of requests are shown in console.