When exporting to .glb in 3ds max 2023 using Babylon’s max exporter, glTF materials set to “Unlit” will become exported with the albedo set to completely black. This makes the materials appear black, and manually setting albedo to white is required to fix this.
Albedo does not turn black when using a PhysicalMaterial set to “Unlit” under the Babylon Attributes.
Neither does it turn black when using 3ds max native glTF exporter.
Only the glTF Material has this erroneous behavior.
Since Autodesk made some changes to the glTF material in the latest 3ds max update I think a bug might have happened in the Babylon exporter.