In patron page, you may see issues of patrons linked by garantor. Actually the Ajax call on svc/checkouts fails to send several borrowernumbers, only first one is sent.
It turn out it does not appear on master, it is caused by Bug 15219
(In reply to Fridolin SOMERS from comment #1) > It turn out it does not appear on master, it is caused by Bug 15219 Missed the next comment...