RHEL7: nc: invalid option -- 'z'

Installer fails on RHEL7 (See https://jenkins.open-xchange.com/view/QA/job/qaInstall-Pipeline/605/consoleFull)

nc: invalid option -- 'z'
Ncat: Try `--help' or man(1) ncat for more information, usage options and help. QUITTING.

Installer seems to run in an infinite loop