Just stumbled onto this (and a few others like it) thread, and a few things stand out to me:
This problem seems to occur usually after storing the records without using them for many years, it also seems to appear pretty much instantly , I can't find any examples of records which appear to have slight "misting" , it's either there, or it's not.
This makes me wonder how the records were stored: A Garage or attic can reach 50 degrees celcius on a sunny (summer) day, even in our moderate (Dutch) climate, I'd imagine they could probably get considerably higher in a country like Australia or Thailand.
I'm no chemist,and am just speculating here, but chemicals/solvents/petrol/paint etc etc. are also pretty common items in garages and attics, maybe they can contribute to these problems when evaporating in a poorly ventilated, sun baked storage? (I vaguely remember a story about a guy who had his entire Cd collection "glaze over" after storing it in his garage for just a few weeks, and blamed the petrol fumes / heat combination)
It certainly appears to be a problem that requires a very specific set of circumstances to occur, but which affects a considerable perecentage of the records once these criteria are met. I have never encounterd it, or even heard about it in the Netherlands.
Edit: Some interesting reading: http://www.plastiquarian.com/index.php?id=7&subid=127
PVC has it's own subsection under "problem plastics" a quote: "Polyvinyl chloride: Deterioration: Light causes yellowing and darkening and can lead to the giving off of hydrochloric acid."