Decal not showing on block instance using Flamingo nXt 5 in Rhino 5

I created a simple cylindrical trashcan model and assigned a decal to it (using cylindrical mapping). When I render this model using Flamingo nXt 5, the decal shows up as expected.

Then I inserted the model as a block instance into another model (empty room with 4 walls) - the block instance shows up but it has no decal. (I guess this is correct behavior?) I manually re-added the decal (now onto the block instance) but this time, the rendering doesn’t have it, no matter what I do.

The decal placement can be edited in Rhino 5 (and then the decal image is visible) but when I render the scene, the decal is missing.

How can I get a decal rendered on a block instance?

Edit placement:

Rendered image from Flamingo nXt: