Add Title flashes on new post screen when post type does not support titles

[jeremyfelt]

Description

The title field flashes on the new post screen when a new post is added of a custom post type that is registered without title support.

Step-by-step reproduction instructions

1. Register a post type with no title support
2. Add a new post of that type
3. See "Add Title" flash on the screen and then disappear.

Expected behaviour

The "Add Title" field is not supported by the post type and should not appear to the writer.

Actual behaviour

The "Add Title" field flashes on the screen.

Screenshots or screen recording (optional)

Code snippet (optional)

https://gist.github.com/jeremyfelt/18ef1d88a978220f5333819ef50d1dc5

WordPress information

• WordPress version: 5.6.2
• Gutenberg version: 10.0.2
• Are all plugins except Gutenberg deactivated? No. There is also a POC plugin that registers this post type.
• Are you using a default theme (e.g. Twenty Twenty-One)? Yes

Device information

• Device: Laptop
• Operating system: MacOS 11.2
• Browser: Firefox 86.0 and Brave 1.20.110

[Thelmachido]

@jeremyfelt is it possible that the fix for #29921 also resolved this issue?

If that is the case we might need to close this issue.

[jeremyfelt]

I still see this in WordPress 6.2 with and without Gutenberg 15.7.0 active.