You can discard humidity as the root cause, I live in Madrid and it's almost a miracle each time we see any rain. And my DSOTM continues being dead.This article is a good overview of the problem, and mentions a culprit that I have suspected: humidity. If you live in a humid climate, you might consider a dehumidifier in your storage area to help delay the onset of problems.
I live in a very dry climate, and played my DSOTM tonight in a BDA-95 with no issues.
I'd discard any issues with the polishing of the disc surface as mine is pristine
Someone suggested contacting Mr Loasby directly, I'd support that!