i was picking my machine up other day from Dry fusion and while i was there a guy local to me dropped off an Airflex for a new pump and i could see the waste tank dome you mentioned was covered in what i would say is resin it looked a mess, so i presume they have had the same problem and fixed it this way.
spot on for customer service.... and for that reason my next machine will be a storm..... cannot wait..... just need to clean enough carpets to pay for it! question is, do i sell my very well looked after pro, or keep it as a back up machine......