Rangefinder Sonar override what can happen?

Hey, i have some custom build using arduino ESP8266, lua scripts on FrySky, wholoe thing is to control basic functions of Gopro 8 with WiFi UDP pockets, and sending data back to FrySky with telemetry passtrhrough. My setup is, that i use 14Channel on FrySky radio, to control gopro, and on Pixhawk i use Channel 8 RAW ovveride, i’ve connected it to Aux 5 (yes ch8 -> aux5 on pixhawk), i’ve setup the aux5 as rangefinder pwm, and it’s working, i’ve got the data back from gopro -> esp8266 wifi ->pixhawk -> frysky telemetry sonar 0x5006 packet.
Now i want to do some fly tests, and i’m little confused about behavior of copter with sonar values being jumping from 0 to 2000. Can somebody tell me if there is some danger with it? I have set the EK_ALT_SOURCE as 0-use Baro, is there somewhere else some parameters to set, in the way the copter won’t take sonar/rangefinder value for fly or crash control?