That actually happened with the record I just uploaded. I was with 5 crates collected as can be seen at the crate counter (nearby Turn Time), but I had x4 HHGs only, because I got a Select Worm from the 4th crate I collected (the scheme is already with infinite Select Worm, by the way). Fortunately I was lucky to find a 6th crate on my way that I decided to collect, containing the 5th HHG needed for the challenge. All the crates I collected of this replay spawned on my way, including two that were very close to each other. There was even a 7th one very close to me that I decided to ignore.