Now for something even funnier: Start with your app activity off and click on the My Stuff page. In a second tab open the Gemini app activity view and turn it on. Switch back to the main Gemini page but don’t touch anything, just wait about 15 seconds (EDIT: you might have to remove focus from that tab for a second, such as switching to another tab and back) and you should see every file you have ever generated pop up, whether you did in temporary chat or with activity off. You can try double clicking on them, sometimes it works and brings up the entire chat containing that file.
Whether this reveals something about the truth with “deleting within 72 hours”, or if it’s just a bug, who knows. Hope someone at the Gemini team sees this because this is just crazy.