Looks like upstream released 5.10.17 https://community.ubnt.com/t5/UniFi-Updates-Blog/UniFi-Network-Controller-5-10-17-Stable-has-been-released/ba-p/2676018
Created attachment 202218 [details] Proposed patch for unifi5-5.10.17
The unifi5 port is updated to 5.10.19 lately. So this PR is outdated. But there is a 5.10.20 released in the meantime also. https://community.ubnt.com/t5/UniFi-Updates-Blog/UniFi-Network-Controller-5-10-20-Stable-has-been-released/ba-p/2713745 As it is releases so quick after 5.10.19 I guess it has some 'last minute' fixes.
A commit references this bug: Author: feld Date: Wed Mar 20 22:15:08 UTC 2019 New revision: 496391 URL: https://svnweb.freebsd.org/changeset/ports/496391 Log: net-mgmt/unifi5: Update to 5.10.20 PR: 235866 Changes: head/net-mgmt/unifi5/Makefile head/net-mgmt/unifi5/distinfo