A widget has not been bound to the form in a relation popup form

my models setup are a model Lesson who has many quizzes.

inside the lesson form, i used the classic relation manager to be able to add a quizz to my lesson.
The popup shows up.
In for popup form there is a repeater to add options to the quiz as per screenshot below.

I have to save the quiz first and before I can options to the quiz.
Otherwise, i have this weird error because options is not even a relation but a jsonable

I tried with deferredBinding: true in the config_relation file but it does not fix the error.

Any idea on what is going on here please and ow to solve this ?