Hi @jmb2021,
I think there’s a bug with the Marketplace Deck Swiper. If I have a update action to add the users to a many to many rel property ( following and followers ) it doesn’t add all users and adds sometimes 2 users ,1 user and sometimes working well 
( not sure if other makers facing this same issue )
I think best is to Submit a Support Ticket and Adalo Team and the component developer ( Minimum Studio ) will solve this issue together! Or I think you can contact Minimum Studio.
Did you tried the Pragmaflow Deck Swiper? : Guys Check This Out!
Thank you