Exposed metal duct in attic – GreenBuildingAdvisor

Yes to both issues. Condensation on the exposed metal is real and it does cause leakage stains inside when the water runs down onto the drywall below. This condensation may get worse when the duct is buried in insulation because the duct will now be colder due to the effects of the insulation. While the duct is colder, there is nothing stopping the humidity in the attic from moving through the insulation and condensing on the duct.

As far as the fiberglass peeking out, that can be an indication that the end of the insulation is not properly terminated on the duct. It is also sloppy work, though this is somewhat understandable in a blazing hot attic. If there is an inner sleeve on the duct insulation, it should be sealed to the duct with mastic to keep attic air from between the sleeve and the duct. The outer sleeve should then be pulled up flush to the next feature (ceiling, another duct, etc.) and clamped in place with a Zip tie. The clamping keeps the insulation in place and squeezes the insulation enough that no air and moisture will get into the insulation.