Bug Static objects are black in Android build after baking lightmap

I have a problem that is plaguing me in what I expected to be the easiest part of my workflow.

When I bake lighting into this scene, it's fine in the Editor, it plays no problem, but as soon as I build it to Android, everything goes awry. All non static objects use the same exact material, Lightweight Render Pipeline/Lit, I'm on Unity 2019.2.10f

Here's the game as seen in the Editor,


And this is what I get after deploying to the device,


Emission works fine as you can see, and my other shaders, ie. those fake light beams, work like a charm. The doors aren't static so they look fine, they do use the same material as everything else though, it's only things that have been included in the lightmap that are doing this.

I've been sat here for 18 hours drowning myself in coffee and nicotine trying to work this out, tried all kinds of solutions but I've come up empty.
Is the lightmap being excluded from the build?? Is this a known bug? What's going on here?????