After months of struggling with the “zombie post” issue on Hackers' Pub—where deleted posts wouldn't disappear from remote servers—I had a sudden hypothesis today. As I dug into it, I realized it's a structural issue with Fedify's MessageQueue system: Create(Note) and Delete(Note) activities can be delivered out of order, causing remote instances to receive Delete(Note) before Create(Note).
The fix will likely require API changes, so this will probably need to wait for #Fedify 2.0.0.