Thank you for notifying about this, I think WorPress 4.8.2 is causing this, I can confirm WP 4.5 is working fine with head widget as you can see in this demo http://demo.themonic.com/publisho-pro/. Please wait for WP 4.9, we will also keep looking for solution and update Publisho Pro if it needs to be updated.
Please direct future Publisho Pro support queries directly to
[email protected]
Update: We have released a new version on 27th October. Please download from the member area.