More specifically, I'm wearing the portable hole, greased bowling shoes, and red cape, but when I enter the Crash Brothers location, the message I get is the same as the one for wearing the hole and shoes without the cape ("Smash looks mildly irritated as you run" instead of "Smash looks mildly irritated until he notices your red cape"). I tried equipping the cape in both accessory slots, with and without a second accessory, but it never seems to recognise that I have it. I also tried not having it equipped, and unequipping everything but the required items, same result. I completed the quest twice before (before retcon and on an alt) with no problems.
Edit: I just finished the quest without problems on my alt, so I switched back to Sena and tried again (without changing my equipment or doing anything else) and it worked this time.