SNMP no error when device not reachable

Hi,

I’m successfully using SNMP to get a temperature from network board. But when the SNMP device gets not reachable I’m getting no errors and the value of item stays the same. Even when I delete the transformation.

Number Number_ActualTemp  "Actual Temp [%.1f °C]" <temperature> (Group_VirtualThermostat) [ "CurrentTemperature" ] { snmp="<[192.168.1.4:shakira:.1.3.6.1.4.1.19865.1.2.3.1.0:60000:JS(actualTemp.js)]" } 
Number Number_ActualTemp  "Actual Temp [%.1f °C]" <temperature> (Group_VirtualThermostat) [ "CurrentTemperature" ] { snmp="<[192.168.1.4:secret:.1.3.6.1.4.1.19865.1.2.3.1.0:60000]" }

Is that a normal behavior? I would expect to get null or error, so I can work with that and get notified or something using rules.

Thanks