The problems you’re experiencing are not specific to the DTH…
Based on my testing with the device, it only reports the temperature when it opens or wakes up. It might also report it when it closes, but I can’t remember.
Setting a lower wake up interval with increase the frequency of the temperature reporting, but if you set it really low it might reduce the battery life.
I’m not sure if the device takes a measurement every time it wakes up so if you set the wake up interval to 5 minutes it might just report the same value every time it wakes up until it takes another measurement.
The device only reports whole numbers and if the value didn’t change you won’t see an entry in the Recently tab every time it wakes up. You can verify that a value is being reported every time it wakes up by clicking the device’s temperature link in IDE.
The mobile app has caching issues so sometimes the device changes state, but you can’t see it in the mobile app until you go back and forth between the device and Things tab a couple of times. I doubt that’s your problem, but it’s worth checking the contact value in the IDE the next time it gets stuck open to see if it did change back to closed.
Based on the screenshot below, which is from the device’s advanced manual, it sounds like it can take up to 5 seconds to finish processing an open or closed event.
If that’s the case then the contact closing before the device finishes processing the open event might explain why the closed event doesn’t always get reported.