As of 18.05 the hold-found modal no longer includes a link to the borrower page at /cgi-bin/koha/members/moremember.pl?bowworernumber=xxx There is also no mailto: link to the borrowers email. To recreate: 1. place a hold on an item 2. check the item in 3. observe modal (no links)
Just retested this and in the modal the link to the patron account and the mailto link on the email address now work correctly.