Did you make a change to your popups? It sounds like cached data is not loading (since hero's session stats are not in the cache) and that can indicate that a stat which isn't designed for use in the Hud has been added to a popup. If you added any stats recently try removing them again - these are most likely to be stats related to overall tournaments such as number of tournaments, ROI or money won.
If you can't get it working please enable logging (Configure > Options) and restart PT4. Replay a hand and open a popup - wait a minute or two then attach the PokerTracker4.log file from C:\Users\yourname\AppData\Local\PokerTracker 4\ (which you can access from the PT4 File menu) to a
Support Ticket so that we can see what is going on. Also export your Hud profile and attach that to your ticket as well.
Tutorial: Reporting a problem