Tags model isn't properly persisted the first time the app is run
The itags (intelligent tags) SparQL models are built by downloading RDF datasets.
The graph with the urn:ipg:i:love:itags URI is the graph that contains the tags. On the first run the dataset is properly downloaded and fed to the graph and the tags are shown in the hashmarks menu. But when you restart the application, and browse the itags graph, it's empty. The app then refetches the dataset, and again the tags show up in the menu. After that, restarting the app works as expexted, the tags are persisted correctly, so the issue only happens the first time the app is run (when the RDF graphs don't exist yet).
This problem doesn't happen for the hashmarks graph, but the hashmarks graph is a "subconjunctive" graph (a conjunctive graph persisted in the parent conjunctive graph) while the itags graph is a subgraph of the main conjunctive graph. So this could be related to RDFlib v5, or the graph hierarchy ...