What type of issue is this?

Incorrect support data (example: BrowserX says "86" but support was added in "40")

What information was incorrect, unhelpful, or incomplete?

MDN is showing that Firefox has full support for transition-behavior:

However, the display compat table shows that Firefox does not support transitioning the property when transition-behavior: allow-discrete is set:

It's also broken out on caniuse under the "CSS property: display: Transitionable when setting transition-behavior: allow-discrete" feature:

What browsers does this problem apply to, if applicable?

Firefox

What did you expect to see?

I'd expect to see Firefox have partial support for css.properties.transition-behavior, with a note about the transitionable display issue.

I'd also expect this to affect transition-bahavior's Baseline status to limited availability, because it seems like it doesn't fully work in Firefox.

It probably makes sense to keep the compatibility note on display because the issue affects Firefox's ability to transition that property, but I would have also expected to see a corresponding note on transition-behavior.

Did you test this? If so, how?

No

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

https://developer.mozilla.org/en-US/docs/Web/CSS/transition-behavior#browser_compatibility
https://developer.mozilla.org/en-US/docs/Web/CSS/display#browser_compatibility
https://caniuse.com/mdn-css_properties_display_is_transitionable

Do you have anything more you want to share?

I found out about the support issue in Firefox through https://youtu.be/VA975GOUFmM?si=WvtQxcksDbT_H6m0&t=844. I'm impressed that they knew about it despite the transition-behavior docs suggesting that the feature is Baseline and fully supported in Firefox.

MDN URL

https://developer.mozilla.org/en-US/docs/Web/CSS/transition-behavior

MDN metadata