how to monitor a communication channel on Schneider M340 PLC

so i have an isssue where if the serial port of an M340 plc disconnect from the screen it would retain the values of the variables being sent to it from the HMI meaning it will latch some of the contacts in the program that are like a push button on the HMI
i've tried T_COM_STS_GEN to monitor the channel (tried it from IO Derived Variables and again from Device DDT variables) and trigger a stop with the CH_ERR in it and tried using the time out error but it doesn't change if i disconnect the hmi and the issue keeps happening
any idea how to solve this ???

Simple old school heartbeat timer read clock / time of Hmi if no change in value in x seconds Hmi com loss.