I have a custom object (Volunteer Application) where I'm trying to use custom builder to create a related record (Volunteer Shift). I can create the Shift record, however when I try and populate the ID of the application in a lookup on the Volunteer record it won't work.
I went further to populate the same ID in a text field (external ID) and it worked but I noticed that it's the 18 digit ID, is that a problem? I was thinking of using a field update to trim and update the lookup but that can't be done with a field update. What am I missing??