I think you might be onto something...
In the def.json for my printer, it has this - think it's related?
"machine_disallowed_areas": {
"default_value": [
[[-117.5, 117.5], [-117.5, 108], [117.5, 108], [117.5, 117.5]],
[[-117.5, -108], [-117.5, -117.5], [117.5, -117.5], [117.5, -108]]