Can a standard residential IP address suddenly be flagged as a VPN?

I’ve recently come across reports of users finding their streaming apps suddenly identifying their home network connection as a VPN or proxy, even though they aren't running any VPN software on their TVs or routers.

One specific case involved a user whose connection was flagged after they had used WireGuard to remotely connect back to their home network while traveling. While switching to a new public IP assigned by the ISP temporarily resolved the issue, changing DNS settings or bypassing ad-blocking configurations had no effect.

This makes me wonder exactly what criteria streaming services use to determine the nature of a connection: is it the reputation of the public IP, a mismatch caused by lagging geolocation data, or the activity of accounts and devices associated with that IP?

Has anyone else experienced a situation where a legitimate ISP-assigned IP address was misidentified as a VPN after traveling? How was the issue ultimately resolved? Did you obtain a new IP, wait for the system to remove the flag, adjust routing settings, or switch to a dedicated residential network line?

I am particularly curious about how the behavior of a "residential VPN IP" differs from simply routing traffic back to one's own home network connection.