What data is sent to my devices?

I have a Romotec D_HVAC_ZoneThermostat which has been presenting some odd behaviour and was wondering what data is sent to the unit from Vera?

For instance, on several times the time on the head unit resets to 0000 and is out of step with actual time.
I’ve noticed that on occasions (when swapping in new batteries) that there is no need to set the time as it gets Vera time on polling. This also occurs if the batteries are not changed, but there is no logic as to why, when or where.
This lead me to polling the device more frequenty, alas, this isn’t a solution either.

So my question is “What data is sent between Vera and “the device”” and does this include a time check?
It appears to, but there is no consistency, any ideas why and how to force the time update?

I don’t know which model thermostat this is, the D_HVAC_ZoneThermostat Vera’s generic naming. I’m only aware of two Remotec products related to thermostats.

If you are referring to the ZTS-100(Manual here.), then yes, Vera can/does set the clock. Page 30 shows that the thermostat supports COMMAND_CLASS_CLOCK.

When and why Vera does anything to the clock is a question that you would have to put to MCV.