Hi!
I have a tub of smoothover walls which I bought to try to improve some rough painted-concrete walls in our 1950s kitchen.
I have had the tub for a few weeks and opened it a while ago to do a small job.
I opened it tonight and it was completley covered in velvety black mould!
I have scraped it off and it does not appear to extend below the surface so it presumably likes the solvent liquid in the smooth-over.
Has anyone else found this?