dasher.toggle event not fired the first time the user menu is opened (only on mobile)

[Siderite]

Exact URL of where the bug happened

Any lichess URL

Steps to reproduce the bug

1. Open lichess in desktop mode
2. Add a display logger to pubsub.emit and open the user menu - a dasher.toggle event is fired
3. Open lichess on a mobile or with mobile emulation
4. Add a display logger to pubsub.emit and open the user menu - a dasher.toggle event is NOT fired, but it is fired when the menu is closed and any reopening it from then on

What did you expect to happen?

I expected a dasher.toggle event whenever the menu is open or closed.

What happened instead?

Inconsistent behavior between mobile and desktop, probably related to MutationObserver.

Operating system

Windows 11

Browser and version (or alternate access method)

Brave, Kiwi

Additional information

No response