Working on a little Scene and im using a Substance Source Material in the Marmoset Toolbag 3 Trial - its set to 2k x 2k and I ,,placed,, the Textures.
When opening up the Scene in Marmoset Viewer the Texture is unusable - all the other Textures look like they should ( exported from Substance Painter )
Edit: exporting the textures with high/unreasonable settings dont change the appearance
Marmoset Toolbag 3:
Marmoset Viewer: