It may be that you're seeing those nodes and messages stored on the Android app (now unknown since the node has indeed factory reset). There may well be a separate option in the Android app to clear the node database from the app.

To be sure, you can check the nodes on the device directly using the Python CLI, with the command meshtastic --nodes. If you see none (or a handful in the seconds since the factory reset) then it is resetting as expected. If you see them all still there then it's not.

Clearing the node database before or after factory reset doesn't seem to make any difference.

It may be that you're seeing those nodes and messages stored on the Android app (now unknown since the node has indeed factory reset).

I don't believe the android app perpetually stores nodes. They seem to be stored in a volatile fashion. They will stick around when disconnected from a device. But when reconnecting it pulls down a fresh copy of the node DB stored on the device. Regardless, it's not possible to narrow down the issue to app or node unless @madeofstown provides the output from the CLI on a node query.

Sorry, I've been working on other projects. I'll try to get around to capturing CLI output from the node this week.