Per our troubleshooting in the comments, this appears to be due to the JavaScript implementation of Google Analytics (as opposed to the typical placement of the provided GA script in the document <head>
(as revealed by the lack of output from the GA Debugger).
I'm not familiar with the script provided by Peaks & Pies (linked in the comments above), but I would wager that even if it was working, the data may not be as accurate as simply placing the GA script in the head. Since it needs to wait for JS to call a pageview, I'd be worried about particularly the bounce rate data being slightly lower (since users may leave prior to the pageview even being sent).
Sounds like placing the script in the <head>
has worked since the GA Debugger is now outputting data. Might even be worth opening a ticket with Peaks & Pies.