Mold showing up at a few registers after blowing in insulation

[clarker]

I live in florida and 4 months ago had fiberglass insulation added in my attic over the 20yo stuff that was not sufficent. We added enough to bring it up to R45 which covered existing HVAC ductwork. Just recently some mold began appearing at a couple of the registers. I am sure the ducts we covered. Could this insulation covering the duct work be causing this mold to apprear? Thanks in advance for your thoughts.

[beenthere]

Yes, specially if he registers and register boxes/boots aren't sealed to the ceiling/attic side.

[duckman06]

I agree with beenthere. I would pull down all the registers in the home and look for gaps that would be letting non condition air meet condition air. If this is the case get a few tubes of caulk/silicone and seal the gaps. Replace the registers that are discolored. Also might want to replace them all so they will look the same.