Hi Michael Brunak. Did you deploy to a new site collection or try to deploy to an existing site collection? I haven't tried using the app catalog to deploy to different site collections. I used PnP to deploy to a new site collection and it works fine.
AmyDolzine, did you managed to update the deployment? The process is here on the Github repository. In short, you'll need to download the package and update it in the App Catalog. https://github.com/pnp/custom-learning-office-365/blob/master/README.md#current-release-version
sofiamaxe, I have found that you'll need to create a custom playlist and then mix your custom pages/content. I have been creating custom playlists anyway because the default playlists don't deliver the info in an order I agree with. I work with my customers to prioritise their scenarios, then order the content in the playlist to compliment the delivery of our in-person training and drop-in sessions.