[base-ui][Transitions] Exit transition is broken since v5.0.0-beta.33 in the Popup

[fnlctrl]

Steps to reproduce

Link to live example: (required)

Steps:

1. Click any of the "Show popup" buttons
2. Click "Hide popup"
3. Notice the exit transition is missing

The previous working example can be found by cloning the repo and checking out 5d7c4e2 (one commit before #40524) and starting the documentation

Recordings:
v5.0.0-beta.32 (working)

v5.0.0-beta.33 (broken)

Current behavior

Exit transition it not being shown

Expected behavior

Exit transition should be shown

Context

No response

Your environment

npx @mui/envinfo

  Don't forget to mention which browser you used.
  Output from `npx @mui/envinfo` goes here.

Search keywords: base-ui, transition, exit, popup

[danilo-leal]

I also noticed the same while working on some Base UI demos earlier today — the exit transition does not seem to work in all Popup demos from the Transitions page.

[cjz9032]

any updates?

[michaldudak]

With the release of @base-ui-components/react, we consider the @mui/base package deprecated. Going forward, we'll focus only on the new package.