I noticed that you put the files in the texture folder of your sceneries into the Global section of P3D v4 (at least with my installations) instead of letting them be as a subfolder (as is the scenery folder) like via the "old" Installation where you select the prior scenery folder in the scenery.cfg:
We don't put any textures files in any folder of the sim. They are located in the \texture folder of the scenery, as they always were.
The Global keyword in the add-on.xml file doesn't mean the textures will "go" into the Global folder of the sim but, instead, will be accessible from objects not necessarily located in the \scenery folder of the scenery, which is the case of the Simobjects that calls them, which makes for 95% of the scenery objects.
I believe you think the Global keyword wasn't necessary because the texture still work, but that's just because the Simobjects have a fallback in their texture.cfg so, they will work regardless but, I guess that adding the texture folder of the scenery in the add-on.xml might be a bit faster than forcing the sim trying to open textures, not finding them, and then relying on the fallbacks on the texture.cfg file of every Simobject folder, open them individually, to finally find them.
