We have no idea what's smoking and why. Generally you would check the voltages to see what's incorrect. If this was happening but isn't now, it could be debris in the amplifier that was causing a short but has been dislodged, or some other bits touching that shouldn't be, which have now been moved apart.
I have never seen a defective 6080 do what you're describing, so I believe it would be a mistake to assume this is tube related.