This is very strange. I got Secrui M520+F55 wireless doorbell. My Wifi is secured with a pretty strong password. I plugged the Doorbell in and Glasswire reported that my Texas Instruments doorbell connected to the Wifi. I did not give it a password and I did not push the temporary no password button on the router. I am concerned that this doorbell was able to connect. I knew it was wireless, but I don’t see in the manual where it is even a wifi doorbell. And even though it is Secrui it shows up as Texas Instruments which might just be the internal circuit. It’s very strange. I do not have any other doorbells.
Whilst this is a wireless doorbell. I am also seeing no indication that it has the capability to connect to Wi-Fi. I think the Texas device is something else. Perhaps remove the batteries from the Secrui and see if the Texas remains connected. Could it be a neighbour?