Currently, when a reference contains a constraint violation, the section is unfolded, in order to help the community seeing the problem and fixing the reference or the constraint.
When the constraint is not fixed for some reason (non-mandatory constraint, exception, disagreement between editors), the reference section would stay unfolded, making the reading and editing experience more difficult.
A suggestion would be to make the difference between mandatory and non-mandatory constraints: when a reference section contains only non-mandatory constraint(s), it could stay folded.
Follows this discussion: References_not_to_displayed_unfolded (Dec 2018)