Let's Control It

Puzzled and therefore next request for enlightment (if possible) ........

When looking in my wifi-environment with my mobile phone and my iPad, at 2.4GHz ch1 as WAP an SSID pops up called ESP_21, which could hint at an ESP after startup.
Not showing a suppliername, WPA2 active, not accessible with the default start-password configesp as for ESPEasy.

All ESPs incl. NMCUs under my custody and all my other devices incl. WAPs operating on Wifi are accounted for in 'application-mode' linked to my LANs.
My neighbours hardly expected to operate ESPs or NMCUs.
The wifiscanner on my mobile phone (= Samsung A23) estimates this ESP to be at a distance of approx. 10m~35m, different from the info related to the known WAPs.
MAC-addresses visible:
- on mobile starting with 5E
- on iPad starting with 6A

Therefore just surprised and wondering => the question:
which ESP-configuration at startup in AP-mode identifies itself with ESP_21, and how to further access?

I have also seen this to happen when the config of the AP mode of the ESP has not set the hostname.

ESPEasy _should_ not show this, but as I said I have seen it happen.
On the other hand, there are quite a few cheap (sold by Action) WiFi 'smart' LEDs using ESP processors.
So those could also show this behavior

The distance estimation might point to my neighbours unknowingly having fitted such cheap Action_LED_device ........

Maybe you can walk around the house to see if the distance estimation makes sense so you can do some triangulation.