Custom Field: Dropdown box

From the description of the issue the most likely problem that occurred when the Dropdown Fields were created and saved as a Custom Field was the use of the same Data Label on the dropdown fields. If you have two dropdown fields with the same Data Label, lets just say “Scale”, and you add two of these Custom dropdown fields to the same document/envelope, then they act as if they are linked and choosing one option on one dropdown automatically chooses the same option for the other, this is called “field duplication”. I would suggest creating new dropdown fields and making sure the Data Labels are unique and then see if the same issue occurs with these new custom fields or update the “Name” of each custom field so they are unique, so Scale1, Scale2, Scale3 etc.

You can also create the envelope, add the custom field, and then with each custom field make sure the “Data Label” for the field is unique before you send the envelope. This way you have 1 custom field but each time you add the custom field you update the Data Label to  a unique value so you do not get “field duplication”.