Material of Destructible Mesh Not Showing In Packaged Executable

I’ve searched the forums for this but have not found anyone who had this issue.

[Currently using engine version 4.10.4, but it also happened in 4.10.3, and possibly back to 4.10.2]

We are early in our prototype phase and put some destructible cubes in our level. They were created from a basic cube static mesh with a material from the Starter Content applied. When run in the editor, the destructibles look fine, but when we package an executable (via File –> Package Project…) and run the executable, the destructible meshes have no material other than a plain gray one.

The first picture shows when it is run in the editor (the lower left is the standard static mesh and the upper two are destructibles).
The second is from the exe and shows the destructibles without material.

I thought about it not having cooked or packaged the needed material, but then I figure the static mesh would not have it either.

Can anyone confirm destructible meshes having correct materials in packaged executables, and/or any ideas?

By the way, we packaged it using the Development build configuration rather than shipping since we are using Steam and, as per other threads, Steam has problems when using a Shipping configuration.