Error Message: "Please specify an email address to send to", when creating transactions even if To Be E-mailed is not shown and not mandatory

Consider the following scenario:

-       There are Customer records without Email.

-       The To Be E-mailed field under Communication tab > Messages subtab is not shown in the preferred form which is a custom transaction form.

-       From the Customer record,  user created a transaction and received the following message upon saving:

 

"Please specify an email address to send to"

 

This occurs if in the Customer record > Preferences subtab, Send Transactions Via Email checkbox is True (checked) and cleared the field for the email address to be inputted. This preference must be set to False (unchecked) to be able to save transactions for customers without an email address on their record.