Try this:
WHEN ARM AWAY
THEN FLAG 1 ON
WHEN JOY OFF
AND IF FLAG 1 ON
THEN MAIN FLOOR THERMOSTAT HOLD OFF
THEN MAIN FLOOR THERMOSTAT MODE HEAT
THEN MAIN FLOOR THERMOSTAT HEAT SETPOINT 19
THEN FLAG 1 OFF
The first block turns on a flag when the system is armed in the away mode.
The second block should execute the desired effect "only" if Joy disarms the system and it the system was in the Away mode.
If the above does not work, use a console to confirm the controller you are using has firmware version 3.0 or later. If yes, then break down your programming to the most simple basic, confirm that it works, and then add to it until it either breaks or achieves your desired effect. If it breaks, report here what you had and what you added to break it.