Issue with Cover block (or any background image) on Multisite

[HardeepAsrani]

Describe the bug
If a site admin (not Super Admin) uses Gutenberg and tries to upload a background image to Cover block or any other blocks with background (custom), the background is stripped away and the block breaks on the backend.

However, still works for Super Admin. Tried with fresh Network without any plugin apart from Gutenberg.

Video in the bottom.

To Reproduce
Steps to reproduce the behavior:

1. Make a MS setup with a subsite.
2. Make a new user and set him as Admin for the subsite.
3. Open Gutenberg and add Cover block with a background.
4. See it in the frontend. Refresh and see it on the backend.

Screenshots
Video of the issue as an admin:

https://drive.google.com/file/d/1G-1SqJMUH-CaDyiZ1uIapAl8DA5LaFnw/view?usp=sharing

Desktop (please complete the following information):

• Latest MacOS
• Firefox, Safari and Chrome

Let me know if any more info is needed. Tried in many different places on many different Multisites.

[Soean]

Hey @HardeepAsrani,
thanks for reporting this problem.
We already have an open issue about this, see #2539. We are working on a solution, that solves this issue in one of the next versions.