[Koha] software error when user not superlibrarian tries to find a patron

[Carolina Andreu]

Hello Koha community,
We've found that when a librarian has some permissions (catalog + borrowers)
but not superlibrarian and syspref IndependenBranches is turned on, we get a
software error when this user not superlibrarian tries to find a patron
within the patrons module: Can't call method "branchcode" on an undefined
value at /home/www/our_koha/intranet/cgi-bin/members/member.pl line 56.

Still, this user is able to find the same patron searched before if
cardnumber or borrowernumber is used instead of name. 

We're working on Koha 17.11 + Debian 8.

Has someone experienced this behavior and could give any clue? Should we
report this as a bug?

Thanks in advance!