Heating not coming on at night as per schedule, but fine in morning!!

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Hi. Have had tado system for about 1.5 years and no issues. Last two days has been acting strange. Tuesday night the heating hadn't come on as per usual schedule, boosted heating to all rooms and can see the signal is getting to the receiver as the lights for heating and hot water are on...but nothing from the boiler.

Assumed was a boiler problem so scheduled engineer to visit. Randomly at 10pm that night the heating came on even though it wasn’t scheduled to. Next morning heating worked as per the schedule and turned off fine. Came on again at 4pm as per the schedule in our office (have the separate radiator thermostats). We went out and came back again to no heating!! Tried boosting to all rooms but nothing. Thought it would come on again at 10pm but it didn’t. Woke up at 3am and it had come on again!!

Fine again this morning as per schedule. At 12pm today we did a boost all heating and it came on fine. Really really strange behaviour. Haven’t changed anything in the house, checked all the batteries in the valves. Boiler seems to be okay so not sure what to do now!!

We have the Starter Kit – Wireless Smart Thermostat V3+ and separate radiator valves in each room. Any ideas or suggestions? Has anyone had something similar happen? Not sure if I need to reset / reboot things? Redo the scheduled again from scratch?! Any and all suggestions gratefully received!!! Thanks!