I'm going to vote for both. Sounds like the engine JUST went in. I wouldnt want an odd return tube...but I'm OCD
HOWEVER. In your case, I'd probably do the collapsing tube for now and go ahead, make sure everything runs right. Then pull it back out and fix the tube along with anything else you might find.
The only thing worse than pulling the engine apart to replace the tube, is finding yet another thing that might make you pull it apart AGAIN later.