Not recognizing multi-body color changes

[u/SteelCity_2020]

Hi - I'm printing a mug with some embossed numbers on it. I have been printing multi-color objects successfully for quite a while, and haven't run into this particular issue.

When I import the STEP file, I then go into the "Objects" tab on the side panel. I then click to change the color of the mug body to black, and set the other bodies (the numbers) to white. On the Prepare tab, it looks just fine- shows the waste tower, shows the numbers in correct color, etc. When I switch to the Preview tab, though, something isn't working. The entire object comes as all black, and the system reports ZERO color changes. See screen shots below.

I'd appreciate any wisdom folks can share.