PULSOUT is a toggle. Sooner or later you will get some interference that flips the state of the SERVOOUT line and your system will be off in the weeds.

To guarantee correct working of the PULSOUT command you should first force the SERVOOUT line to a defined state.

For example, put
SERVOOUT = 0
or
LOW SERVOOUT
before calling the Pulsout command.

One of my RC aircraft went berserk because of that little oversight.

HTH
Brian