I have Unity 2018.1.0f2 installed. I see no way to upgrade or install the 2018.1.1f1 version, as it’s not listed.
I’m using Unity Hub 0.17 on a Macbook Pro.
Was just about to post the same.
I am using Windows 10 though.
EDIT: Ah fixed it. I had to force close the program and restart it. The Hub never checks for updates while its still running 
? This PC can be powered on for days sometimes.