Why is there cooling in deadband during night

edit

I have a problem with an energy model I am working with that I would like to discuss here. I would appreciate any advice since I am a beginner in this. I do not know the reason that we have cooling in deadband during the night. In the model, the cooling setpoint rises to 26[C] at 10 PM and heating setpoint goes down to 15[C]. the problem is we have cooling during the night until the zone temperature gets to heating setpoint! I would appreciate any help in this matter.