An instrument gives a reading at a particular place and time. The three bed markers in the picture are different locations from the instrument standing in room air. A reading from air should not be recorded as if it came from the growing material.
Use a consistent location code: room, rack, tier and position. Record time, crop stage, instrument and recent changes such as watering or a door opening. Compare locations at reasonably comparable times, using a method suitable for the quantity being measured.
If one location behaves differently, repeat the observation and check the instrument before changing the whole room. Investigate airflow, loading and material history with the responsible operator. The picture does not specify the number, depth or placement of sensors needed on your farm.