In Koha 20.05 and 19.11, when a Professional Patron Category patron and a Organizational patron category patron are linked, from the Professional patron, there is a tab to see the 'Relative Checkouts', but Koha just will spin and say processing. Koha is looking for a first name to link the relative checkouts from a professional to the linked Organizational patron. On an organizational patron, there is no first name and therefore Koha can not do the link.
*** This bug has been marked as a duplicate of bug 26797 ***