Set 3368 Space Centre missing one 4211805 I've just bought a second hand 3368 Space Centre and I think there is a mistake in the instructions. According to the inventory there should only be one 4211805 in the pack 



but the step looks like it requires two



The set was listed as complete so my question is, did Lego make a mistake and ship these sets with only one 4211805, or did the seller just go by the inventory and therefore leave out one of the 4211805s that came in the original box?
This looks like an oversight in the inventory printed in the instructions. Your interpretation of the instruction step requiring two of these is certainly correct.

The Bricklink inventory shows 2 of these, so that's what would have been included in the box. The replacement parts page on LEGO.com also indicates that this set should include 2 of the 7M axles.

It's likely that the seller just checked against the printed inventory and didn't include the second axle due to the misprint.