Tyre sensor showing PSi readout, but it's not connected to the wheel

I had a flat tyre recently, but the sensor on the wheel with the puncture was showing 37.4psi - even when I took the sensor off the valve stem! I’ve deleted and reinstalled the app, reset the bluetooth dongle, taken each of the other sensors off (they show as a flat tyre when removed, which is correct) - but nothing is clearing down the data on the phone that is showing the incorrect information. I’ve been in contact with support, which has been somewhat drawn out. I was directed to buying a new sensor, which is fine but i wanted to see if there is anything i can do to test and make sure it’s definitely the sensor, as ‘something’ is telling the ios app that the wheel in question is STILL at 37.4psi, even when it’s not attached to the valve stem! I keep going round and round, trying to install the beta app so i can remove the sensor and check if i can re-add it (http://fir.nondagroup.com/r1db) but it won’t install on my iPhone 11 Pro Max (ios 13.4) and the profile won’t load on the phone.

So buying a new sensor seems a bit of a gamble, until i know it’s not the bluetooth dongle giving out the incorrect information. It’s clearly stored somewhere as i’ve deleted the app and the sensor isn’t attached to the wheel…

@julieta - any help here?