I'm not sure if this is a bug against plasma-workspaces or net_applet.
But it's plsma-workspace-5.20.4-5.mga8 and and drakx-net-applet-2.55-1.mga8
But the geolocation used for Night Color only works correctly if NetworkManager is used to manage the wifi connection. When connected via net_applet the geolocation either isn't tried at all or can't get a result and the lat/long just come back as 0/0.
Thank you for the report.
Assigning this initially to the KDE group;
as Dan says, the fault may lie with drakx-net, so if the KDE side thinks that is the culprit, please re-assign it appropriately (probably to pkg-bugs, since drakx-net is committed by different people, although tv is the registered packager for it - CC'd).