Make change to a thing does not work

Hi bubblers, I’ve run into a quite stupid problem and been troubleshooting for a while. Would like some insights from bubble experts… So to put it simply, my app has an event page where users can RSVP and cancel their RSVP through a button. There will be a popup that shows up before adding/removing the current user into the database; I use the exact same workflow to add and remove current user but weirdly it only works for adding the user to the event’s list of participants and not removing it…

My troubleshooting progress so far:

  1. It’s not the problem of passing data into the popup. The popup displays the data correctly.
  2. I added breakpoints to the workflow actions that aren’t working (removing users from event’s list of participants) but I did not get any error messages. It went through but nothing happened…
  3. I don’t know how but I was able to “make change to current user” - deleting the event from current user’s list of signed up events - but I could not “make change to the event” - remove the user from its participant list.