Fibaro switch becomes unavailable when used with generic_thermostat

Configuration
1

I’ve got several thermostats defined like this:

- platform: generic_thermostat
  name: Parlour
  heater: switch.parlour_warm_floor
  target_sensor: sensor.parlour_warm_floor_temperature
  min_temp: 15
  max_temp: 30
  ac_mode: false
  target_temp: 27
  cold_tolerance: 0
  hot_tolerance: 1
  min_cycle_duration:
    seconds: 5
  keep_alive:
    minutes: 3
  initial_hvac_mode: "off"
  away_temp: 16
  precision: 0.1

where switch is z-wave Fibaro FGS211 and temperature sensor is binary sensor FGBS001

It works pretty well though i’ve noticed that after a while, when thermostat turns on and off, switch entity becomes unavailable.
So i run into the situation when thermostat sent command “turn off” and changes its UI respectively to Idle state, though unavailable to z-wave network switch stays in “On” state heating the floor despite thermostats thinks it’s off.

The problem can be fixed by either re-interviewing the switch of pinging it though it completely breaks the whole idea of thermostat as automatic floor heater.

I have big deal of suspicion that it is related somehow to thermostat-switch interaction cause being used directly the switch works w/p

Does anybody have any idea what might be the reason or at least how to trace the issue?

Hardware:
Raspberry Pi 4
Z-Wave USB Stick - UZB by Z-Wave.Me

Software:
HA: 2023.10.4

Thank you in advance

2

Most likely your z-wave coverage is poor. You should improve it: find a better place for existing device/devices or buy new one for ‘hardening’ the mesh coverge.