[Koha] Problems searching callnumbers with Koha and ICU

Hi Folks Has anyone hit a problem searching callnumbers with Koha and ICU - specifically callnumbers with SPACE ' ' characters? An example problematic callnumber is 'PZ 7 .W663 1984' Or, has anyone had *success* searching callnumbers with ICU? :) Either way, I'd be curious to hear from you I tested on Koha 18.05.12 and Debian 9.8 Cheers, Mason