Bug in pivot displaying datetime field?

I am displaying a datetime in a pivot in the backend, and even though the value is there in the database table, the form does not display it as per screenshot

        label: inherent.ecourses::lang.course.form.customer.last_digest_at
        type: datepicker
        mode: date
        span: auto

ok I found the issue.

the field was not declared in the pivot fields list but only in the pivot model which is not enough apparently