I did a search and couldn't find anything, and I know it's beta, and just wanted to let the developers know. It could be an OS thing as well.

Running win 11 pro - build 22.000.132. 

The taskbar is set to 50% transparency. When the machine boots the taskbar goes back to the default dark grey color, and to being 100% opaque. If you go back to the transparency setting in start 11, the setting is where it should be, but the taskbar is opaque. If you nudge the slider either way by just 1% the taskbar becomes transparent again. However upon say installing a new piece of software or other actions the taskbar goes back to being the opaque grey once again.

I hope this helps.