The temperature on the motion sensors is not very accurate. Anyway, try restarting Zigbee2mqtt after setting the offset/decimal places in the Zigbee2mqtt UI.
I have restarted and it did not make a difference.
The temperature is 2 degrees off compared to the value returned from my sonoff temperature sensor and midea AC. Those two sensors are .2 degrees different from each other.
You need to keep the device awake (by short-pressing the pairing button every few seconds) before changing settings, otherwise it may be asleep.
Also, the temperature returned by the device is the “on-die” temperature; in other words, the temperature inside the microcontroller. It’s fairly useless because it doesn’t measure ambient temperature like your other devices do (even with an offset the temperature will vary depending on how warm the microcontroller gets, and it will heat up and cool down more slowly than ambient).