Error when adding a new item to REPEAT.

Hi, I have an error that I can't solve in any way. I've already searched and nothing. I have a Repeat that is accessing a ManyToMany Relationship. I did everything according to the documentation and it is reading and saving correctly, but when I ask it to save a new record or edit a record, it saves correctly, but gives this error on the screen. If I cancel the error and see, it saved everything correctly. I'll attach the codes I used. Thank you.