A number of years ago, one of the manufacturers actually stated in their owner's manual, that it was "normal" to see bumps through the roof membrane that was things like sawdust, wood chips, screws and staples that were just laying on the roof when they laid the membrane down. NORMAL?! They're telling the world that they couldn't give a cr@p about sweeping or blowing off the roof before laying the membrane down, and, oh well, if some of this pokes out and causes leaks. Can't remember if it was Forest River or Keystone, but it was one of them.
Lyle