It is possible but not likely that all down calls are secured with SHL command. The SFA command will show any secured floors. DSF will display if anything is secured through IMS, DSFC will clear those.

Check the SCA and SCB scan tables. If the floors have a value of 1, the car would accept only up hall calls for that floor. Don’t know why something like this would Chang though. Are these 16 or 32 bit controllers? I have seen the 16 bit CPUs start to do strange things. Is it a new install with HN cards or. MOD with CNAs?