MSP430FR5043: Instantaneous flow instability at high temperatures for gas metering using this scheme

Hi Team,

There's an issue from the customer need your help:

Hello, our test medium is air, the instrument sets the flow rate 6m³/h, and the temperature test is carried out in this environment.

At room temperature 20-25 °C, the instantaneous flow rate detected by the gas meter is about 6m³/h, and the consistency is good. However, at a high temperature of 50 °C, the instantaneous flow rate detected by the gas meter is unstable and fluctuates greatly. What could be the cause?

Thanks & Regards,

Ben