OHHHHHH.
I think I know what's going on!
I'm using yakyak as a Google Hangouts app in Fedora. And I have run it
with & so it just goes away. And in that same terminal window I
connected to the Fedora 28 server. And normally I don't do that, so
I'm just wrongly blaming the most recent change which was installing
powerline.
Haha! Time for a walk of shame...
Chris Murphy