When I click on a link to an Item in the Hub, I noticed that Uberflip briefly takes me to a page that has parameters at the end of the URL, then redirects to a page without the parameters. Does this mean that Google Analytics is double-counting every Item view?
When you see the URL parameters disappear from the address bar, no redirect is actually taking place. As a result, no additional pageview is sent to Google Analytics (views are only counted once). In addition, the built-in Google Analytics integration will strip the additional URL parameters before sending the data to Google Analytics.
If you are using Google Tag Manager (or another Analytics tool) to trigger the track type of "Pageview", you will still notice page URLs with URL parameters in Google Analytics data when viewing by “Page” (Page URL) dimension. You can consolidate these pages by switching your "Primary Dimension" in Google Analytics to "Page Title". Alternatively, if you choose to connect to the built-in Uberflip Google Analytics integration you will want to remove this type of tracking on your Uberflip Hub via Google Tag Manager.