Steps to reproduce the issue

Create multiple contacts in 1 category. Set Contacts options "Contact Select List" to Show.
Create menu-item contact type Single contact.

Expected result

SEF url when choosing other contact from contact list.
List showing selected contact.
Possibility to reselect initial contact as set by menu-item from list.

Actual result

When accessing through menu-item: SEF url (i.e. /contact)
Non SEF url for other contacts. (i.e. /contact?view=contact&id=2:pr-team&catid=4)
List showing contact as set by menu-item.
Unable to reselect initial contact as set in menu-item.

System information (as much as possible)

Joomla 5.1.1

Additional comments

This problem didn't exist in J3!