Block height drops to 0 on alignment set to left or right

[navxio]

Describe the bug
A clear and concise description of what the bug is.

To reproduce
It happens on my custom block as well as the core gallery block.
Steps to reproduce the behavior:

1. Go to a new post page
2. Click on + icon to add a Gallery block
3. Set block alignment to left/right

Expected behavior
The block to maintain its default height

Screenshots
If applicable, add screenshots to help explain your problem

The blue area represents the selection border, which is overlapping itself since the block height is 0. As a result, one is unable to select the block using the mouse cursor.

Editor version (please complete the following information):

• WordPress version: 5.5.3
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? "default"
• If the Gutenberg plugin is installed, which version is it? [e.g., 7.6]

Desktop (please complete the following information):

• OS: MacOS 11.0.1
• Browser: Chrome
• Version: 87.0.x

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context

• To report a security issue, please visit the WordPress HackerOne program: https://hackerone.com/wordpress.

[annezazu]

Thanks for reporting this! Here's a video replicating the oddness this seems to create for anyone curious:

https://cloudup.com/c79-yZr6bd8

Of note, this only happens with the default state before any images are added.

[navxio]

@annezazu It also happens with a block plugin we're developing..

[navxio]

@annezazu in the meantime, can we ask for a workaround so we can submit our block plugin?

[annezazu]

I'm afraid I can't personally offer a workaround to this but perhaps someone can. I'll add a new label to try to draw attention :)

[glendaviesnz]

This appears to be fixed in WP 5.8 and Gutenberg 11.3, with and without the gallery refactor experiment enabled:

[carolinan]

I have not been able to reproduce this with WordPress 6.0.1.