Can't See Material Preview in Sculpt Mode

When I’m in object mode, my material preview looks like this:

But when I switch to sculpt mode to add mountain ranges, it looks like this instead:

I need to be able to see the continents as a reference point when sculpting, so this is a significant problem. So how do I go about fixing this?

Seems it’s the Multiresolution modifier that’s causing the image texture to get hidden. But why?