Hi, I have made some analysis based on the information you provided, but I am sorry that the abnormal cause has not been located for the time being. As you described, the temperature and humidity in tuya App are normal and keep changing, and I am confused why the humidity keeps 40% in Google Home and HomeKit.
If conditions permit, I hope you can do the following to help me better analyze exceptions:
(1) Remove the abnormal temperature and humidity sensor, reconfigure it under the gateway, and then bridge to Google Home and HomeKit again, and observe the temperature and humidity values in different apps, and please tell me the operation time and the result.
(2) If you have the same type of temperature and humidity, you can also try to replace a hardware for (1) operation.
These are the steps that I can think of for the time being to help the investigation, and I will timely inform you if there are new ideas in the future. At the same time, I also hope that you can synchronize the status of the device with me, thank you very much.