Strang behaviour ping binary sensor

My binary_sensor.ping sensors are behaving strange. Sometimes they are shown in HA as not available as in not exsisting. After a restart of HA the live one’s are back (showing connected) and sometimes after a second restart the one’s who are offline (powerless) are shown as Disconnected.
I have one for the tv which should turn off some lights when the tv is turned off. At random days the sensor is not available and the automation does not work. The day later the sensor is back up and the automation works fine. What could be the cause?

I have Home Assistant Core 0.116.2 running on a pi 3 with ssd. And the behaviour was also with 0.115.x

binary_sensor:
- platform: ping
  name: ip_tv
  host: !secret ip_tv
  scan_interval: 30

The logging only shows such warnings

WARNING (MainThread) [homeassistant.components.binary_sensor] Setup of binary_sensor platform ping is taking over 10 seconds.