Hello,
Could it be that a different MAC address is shown in the router than in the app?
Very unlikely, impossible for the same device. Try to refresh router’s page.
Rare thing, but could happen to some linux distributions on dev boards from my experience
I think it’s definitely the same device with a different mac address.
The device name in the router contained BL602 as well as the device name in the app.
The same device with two different MAC’s at the same time is not possible. You are clearly confusing something. Take a screenshot and show it here.