Also, I notice that if there is a special character in the single line of text field that is used for the lookup column, modern dffs will not try to pull up the modal at all. Like I won’t even get the “No configuration found” error.
Example, I have an ampersand & in one of my single line of text fields in my parent list. In my child list I have that value set in the lookup column. If I then click on the hyperlinked lookup value, nothing happens.