There could be a lot of other factors why mould started to grow, everything could have been there and just needed a trigger to culture the growth.
We all don't know the true facts here as why the discussion but obviously they have done tests to combat mould and maybe as simple as fitting simple variant to the test module to combat this issue may have sorted this.
I'm no mould expert but have worked in a lot of homes over the years and most have some mould somewhere and all in different places.
" They are struggling to obtain a true airborne baseline."
The airborne and surface testing have to match is my reading, so even mould spores in the air had to be killed first then the testing was set back until all this was under control then full testing started again.
All the above is just my opinion reading form the release.
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