Instanced Static Mesh Actors Not Appearing in Packaged Game

It doesn’t look likely. But make sure that all the functions you are using are all accessible without the debug build.

Infact, add an if debug to test that the build isnt debug to help differentiate between editor and published too.

Ps: in the code you shared there seems to be nothing building things?
What is the constructor / who’s calling it at begin play?