Duct lying directly across furnace housing

[Jim Baird]

I've never seen rigid, insulated duct resting directly on furnace housing, along the length of it, just shy of touching a housing extension that provides a connection point for the "B" type vent connector.

As furnace ran, the housing, especially at the connector area, was pretty hot.

I advised getting some clearance there, even though I don't know if the typical foil covered wrap is called combustible.

Anyone seen a similar arrangement?