The previously mentioned bug has been squashed. Here are the details:

In RPG Maker MV, when exporting the project, the file Iconset.png (One large PNG image containing all icons for items, weapons, states, attacks, etc.) would not be included. I suspect this is possibly due to using an imported image separate from the default, or the fact that the image is many times larger. I have not tested and have no intention too unless necessary, as the engine is currently being switched over to GameMaker Studio 2.

In any case, the only fix I had found was to export the data, find where the asset would be stored ([www\img\system] in Windows and [Contents/Resources/app.nw/img/system] in Mac) and replace the image manually.

    - Creater K