I have a few of those around my house as well. However I have noticed that my VOC readings are not consistent, even if nothing in the area of the room has changed. I've reached out to their support about it but they're not much help. One thing I have noticed is a correlation with VOCs and C02, one(C02) seems to impact another(VOC)...which I don't think supposed to be the case. I was digging to the forums awhile back but the only conclusion I came up with is, you can't trust the VOC readings on these (or most consumer) devices...just too many variables and the sensors don't know/measure the full picture. It still bothers me though to look down in our son's room and see VOCs measurements elevated.
There was a moment where the VOC measurement was stuck at an elevated level. The solution was to blow some air in there to knock (presumably) dust off the sensor, which worked. It could be that the VOC sensor is not great, but it could also be that it gets dirty.
