I have 2 V1 contact sensors that currently report a temp in excess of 7000 degrees, both are in freezers to monitor temp.. I believe this may be in error. It started when the driver version for the contact sensor was updated. I thought Iris was aware of the issue but it has been two weeks now and no update to fix it. This is one of the few task I still use the old V1 contact sensors for and now that has been rendered useless.
The operating temperature for this device is 32°F to 104°F (0°C to 40°C). It is a possibility that the freezer’s temperature is low enough to have a negative effect on the contact sensor with long term use in the freezer. You can try to remove the contact sensor from your device list and pair it back.
It has been working for several months and the day the driver is updated from 1.0 to 2.3 it starts reporting a temp of +7000, but yeah it's probably my two sensors. Good call.
My freezer sensors have started working again since the last update, probably just a coincidence. So I guess you can mark this as fixed.