I just started Chapter 8.. I really really hope the Welder's Oil will still drop, or else I'm in serious trouble. (I need 35 more..)
If necessary thing don't drop it must be a bug right?
I don't understand why all this is necessary in the first place... to stop drops when you finish the goal. Not really player friendly.
UPDATE : I'm on Chapter 8 - Goal 3, and everything still drops and spawnes luckily.
But I don't see why it doesn't for some players (as long as they didn't finish the chapter)