2 POPP Smart TRV's - 1 isn't reporting temp unless app page refreshed

I have 2 POPP Smart TRV’s. Both function with edge drivers, exactly the same config as eachother.

However, 1 does not report the current room temperature unless I open the device within SmartThings app and refresh the page, then after 30 secs or so, a reading might appear.

The other 1 is reporting the current room temperature frequently, about every 4 minutes.

I have tried deleting it from SmartThings and performing a factory reset, new batteries. Nothing seems to help. Any idea’s?