If no data is received values should be reset

[GreyPenguin]

If a query is incomplete due to a bad connection to one of the units or if there is not enough light available for the unit to respond, all MQTT values should be set to 0

[GreyPenguin]

So in very short, if a query is not successful I would recommend to set the mqtt value to 0. Another approach would be that after for example three failed requests to one SMI260 the MQTT Power, Temperatures, ... is set to 0