We found a strange bug when using ICU in 17.11 and 18.11 after upgrading from Jessie to Stretch, to be confirmed in later versions: Searching for locations and collections from advanced search in the OPAC/staff client doesn't work using the checkboxes. Redundant quotes are no longer ignored. We found that removing these lines from Search.pm fixes the issue for us: if ( $k !~ /mc-i(tem)?type/ ) { # in case the mc-ccode value has complicating chars like ()'s inside it we wrap in quotes $this_limit =~ tr/"//d; $this_limit = $k.":'".$v."'"; } The patch is backward compatible with Jessie.
*** This bug has been marked as a duplicate of bug 23086 ***