Newer version of HA does not check the state of a toggle sensor (sensor that sends only 1 signal code) and at boot it will be status “unknown”. Move the switch and signal is sent and the status is known. Lets say on.
So at boot of HA send desired status as I explained in the other thread ashscott also mentioned: Report as “good” instead of “unknown” for MQTT binary sensor
Set off_delay for the sensor so that the new ‘on’ signal is a change for the sensor.
Hope this helps.