Perhaps when Lugi footstool jumped on top of Sonic upon his rise during Spring Jump allowed Sonic to do it again?
This was something that was possible to do in Brawl with Snake, actually. You'd let Snake use his Cypher recovery once, & then if you went to try footstooling him, you wouldn't bounce on his head since the Cypher still goes on, & then Snake would be able to use Cypher again. It was something Snake players used for in Doubles especially well because it saved them the trouble of using their C4 as means of blowing themselves up to do it repeatedly.
EDIT: Personally, I don't know if this is a glitch or not. Then again, patches were never a thing for SSBBrawl, so I guess it just feels odd to me if this ever gets patched out or not.