https://community.notepad-plus-plus.org/topic/27212/autoupda...
Thankfully the responses weren’t outright dismissive, which is usually the case in these situations.
It was thought to be a local compromise and nothing to do Notepad++.
Good lessons to be learned here. Don’t be quick to dismiss things simply because it doesn’t fit what you think should be happening. That’s the whole point. It doesn’t fit, so investigate why.
Most tech support aims to prove the person wrong right out the gate.