DO12 - SETLABEL shows all labels

I have a button on one of my toolbars with the following command:

Properties SETLABEL=Star
After the upgrade to 12, instead of a single button, it's turning into a huge row of buttons with ALL my labels in them.

What changes do I need to make to my button to fix this?

Confirmed, looks like a bug in the beta.

Fixed in 12.0.2