The TV presenter and Kai Widdrington performed their latest routine to Rhythm Is Gonna Get You/Get On Your Feet by Gloria Estefan.
And while it started well, the ending went rather wrong as the pair messed up their final lift.
Shirley Ballas praised AJ's "pure sass" and encouraged: "It was on its way to a ten, you are fantastic. It's just unfortunate".
"The rest of it was terrific," Anton Du Beke. "I loved it in general but the ending was... 'PLEASE STOP. I CAN'T BEAR IT.'"
Craig Revel Horwood commented: "You were totally watchable. Yes, the ending was a complete dance disaster darling but that can be fixed... one day. Well done anyway."
"That ending killed me," Motsi Mabuse told AJ. "But all in all this was a powerful Latin dance for you, just keep going."
After the routine, AJ & Kai ended the night bottom of the leaderboard with 30 marks.
She told host Claudia Winkleman: "I'm so gutted because we worked so hard this week. I don't want to get emotional but I just hope everyone at home doesn't think I've let them down."
Meanwhile Kai said: "I think I missed the hand, I take the blame for that one."
AJ and Kai weren't the only pair to suffer an unfortunate evening on Strictly this weekend.
Opening the show, Johannes Radebe and John Whaite - also dancing the salsa - had a similar questionable ending to their routine.
Anton branded their dance "terrific" and joked: "I've lifted a few partners on Strictly over the years that I couldn't wait to put down."
And Craig laughed: "The hips went well, it was a shame about the last lift. I love it when it goes wrong. I absolutely love it. But you had absolutely no chance, you had to just throw him on the floor in the end.
"That normally is a lovely lift. I'd love to see it again working."
Come the end of the night, Rhys Stephenson and Rose Ayling-Ellis shared top place on the scoreboard with 39 points each.
Strictly Come Dancing returns on Sunday night with the latest dance off.