qbittorrent 1.1.15 - WebUI password whitelist doesn't work, broken client addresses

[43615]

There is a subnet-based whitelist feature for the WebUI login prompt (Options -> WebUI tab -> Authentication). On app version 1.1.15, this feature has stopped working (fine on rollback to 1.1.14). The log entry for successful logins reports the address ::ffff:172.16.5.1, which appears to be a strange mix of IPv4 and IPv6. The 172.16 block is probably my Docker address pool configured via TrueNAS.