Velocity and Relative Humidity reports from a ZW15R-N Receptacle

[Vit]

From time to time, I get these (and other wild things) from Enerwave ZW15R-N outlet.

Mar-05 10:23:26 Z-Wave Error
(2) Sensor Multilevel Report for type Velocity received, but the corresponding device Node ID cannot be found.(2) Node/Instance=88/-1

Mar-05 09:01:26 Z-Wave Error
(2) Sensor Multilevel Report for type Relative_Humidity received, but the corresponding device Node ID cannot be found.(2) Node/Instance=88/-1

Mar-05 00:23:34 Z-Wave Error
(2) Sensor Multilevel Report for type 0 received, but the corresponding device Node ID cannot be found.(2) Node/Instance=88/-1

Can I do anything to fix this? And what does Instance=-1 mean?