My Nest thermostat sometimes operates in this manner:

[w3]

• It heats up to the thermostat set temperature (let's say set to 19.5, then it heats up to 19.7), stops, and only turns on again when it drops below 19.5 degrees. -Sometimes it remains on, keeping the temperature at 19.3 all day without turning off.

How do I disable this?"

[Jenelyn_O]

Hi w3,

Thanks for reaching out. I'm sorry for the delay. I'd like to know more about it. A few questions: what type of Nest Thermostat do you have? In what country are you located? Do you see any messages or codes on your thermostat or in the app? Checking your thermostat's Energy History will help you see what your thermostat is doing previously. Also, please gather your thermostat's power readout. 

Check out this guide:

Nest Learning Thermostat and Nest Thermostat E:

1. Go to your thermostat Quick View menu.
2. Go to Settings.
3. Look for Technical Info.
4. Select Power.

Nest Thermostat 2020:

1. Open the Google Home app tap the thermostat tap Settings .
2. Select the Device Information.
3. Choose Technical Information.

Best,

Jenelyn