In the Ultimate Race, when Vert and Gelorum are racing towards the Acceleron's sphere, Vert swerves and collides with Gelorum - sending both RD-09 and Reverb flipping into the air. RD-09, flipping end-over-end, crushes the two fins sticking out of the back of the vehicle. When Gelorum exits RD-09, the fins are back.

A reader of the site, by the name AcceleRacer, has a different view of this:
I wanted to comment on the RD-09 fins error you put in. I watched that scene, and I think the fins didn't get crushed or broken, but I believe they merely folded themselves on the back of the car. This is probably like a failsafe function so the fins don't break off when
struck. I guess they probably folded out again after Gelorum landed, because right after the slow-mo sequence they are gone, then the next scene shows them back. This is just what I think. Take it anyway you want.

RD-09 with its fins bent

RD-09 with its fin back to normal