Better Thermostat: Switch off after reaching target temp

I found the functions of “better thermostat” very good. But I got a problem (or I make an error):
After the target tempeature is reached the better thermostat changes mode from from “heating” to “off”. And it didn’t switch back after the room temperature is falling below the target temperature, so no more heating in the room.
Did I something wrong or is this behaviour intended (or a bug)?
With this behaviour this integration is useless, isn’t it?
Thanks for any hint