Thank you, @Bahbus your expression did not result in the expansion of the delimiter.
So I was trying to append a string from the key column of Table 1 onto the existing enumlist of strings in Column A of Table 2.
I had to use 1 grouped action of two different actions: namely marking the key column on Table 1 using the action type “Data: set the values of some columns in this row” and sending a signal to Table 2 using the action type “Data: execute an action on a set of rows” with the reference action type “Data: set the values of some columns in this row”
Reference action on Table 2 for Column A:
LIST(MAXROW(“Table 1”,“Last Updated”,[Last Profile] = UserSettings(“Profile”))
Now that it works, I have to figure out why it is executing so slow. I press the button, and the app freezes for 4 seconds.