Create a form with a d:text property, that allows multiple values.
The multi value text field is then displayed as a single text field.
When entering a text like a comma separated name "Doe, John" the content is stored as two separate values ["Doe", "John"] in the field.
The text should be stored as a single entry "Doe, John".
The problem also relates to LIST constraints with values that contain commas.
Cause for this Bug is the serialization of field values and constraint values in the forms service that use comma separated string instead of proper JSON objects.