Volume menu bar only showing slider

Good morning.

I rebooted my MacBook Pro for the first time in weeks and now the volume menu in the menu bar is not working the same way as it did before.

When I click on the volume icon I see briefly the full menu but then it collapses to show only the slider. I expected to be able to at least get to "open volume preferences".

I've tried rebooting a few times - both with the "show volume in menu bar" option selected and not.

Only plugged in to external power.

What am I doing/expecting incorrectly? 😃

Thanks in advance.