Shelly TRV not working, causing my room to (over)heat

[matthias]

Hello

I have multiple Shelly TRVs deployed around multiple sites, probably 100+. 
I have about 10-20 of these TRV's that CONSTANTLY need to be calibrated again and again, because they do not close the valve. If I surf to http://IP/thermostats/0, I get:

{"pos":0.0,"target_t":{"enabled":true,"value":19.5,"value_op":8.0,"units":"C"},"tmp":{"value":23.1,"units":"C","is_valid":true},"schedule":false,"schedule_profile":1,"boost_minutes":0,"window_open":false}

yet, the valve is open. The TRV reports a position of 0%, thinks the valve is closed, while in reality it is still open. I have turned on both apply extra pressure and extra force when closed, this resolves the issue on some TRV's, but not all of them.

I need to recalibrate a single device multiple times, until the valve actually closes. I just had to calibrate a TRV 4 times until the "0" position actually closed the valve. This within the span of 2 minutes.

The forums do not have a support option for Shelly TRV - thus I am posting this in a different, irrelevant category, as I see no other option.

What can I try to remedy this situation? I have only had bad experience with these TRV's to be honest...