Switch turning ON despite temperature way over target

[wmoc]

Describe the bug
Current temperature is correctly read to be 19C. Target temperature is set to 5C. I think in this case the smart_thermostat should not turn on the heater. Is there something that I'm missing? The configuration uses default values from readme.md.

Screenshots

Additional context

Entity config:

  - platform: smart_thermostat
    name: Bathroom heater PID
    unique_id: bathroom_heater_pid
    heater: input_boolean.bathroom_heater_switch
    target_sensor: sensor.bathroom_heater_temperature
    min_temp: 1
    max_temp: 28
    ac_mode: False
    target_temp: 19 # in my understanding this doesn't matter as it is only the initial setting 
    keep_alive:
      seconds: 60
    kp: 50
    ki: 0.01
    kd: 2000
    pwm: 00:15:00

[wmoc]

I investigated more and have a hypothesis, that this was a safety mode due to unresponsive temperature sensor. Every heating interval was exactly 60 seconds though. Default value of output_safety is 5%. 5% of 15min is 45s. Is there an and undocumented minimum of 60 seconds of ON state?