I noticed recently (maybe the last few months) the temp sensors would throw a weird humidity value every now and then. It was throwing off my master bathroom fan automation and I finally got annoyed enough to look into it.
Every 4 or so reports it would report a value of 654.4 (and its always the same). Below is the relevant log from one of those reports so you can see the raw values etc its getting. FF9C is the strange value that is reporting. I've confirmed this on a few sensors so not sure if its from a hub change recently (I'm running the beta firmware).
Master Bathroom Sensor: Creating event [name:humidity, value:654.4, unit:%, descriptionText:Humidity is 654.4%]
Master Bathroom Sensor: Humidity is 654.4%
Master Bathroom Sensor: Raw reported humidity = 654.36%
Master Bathroom Sensor: Message payload: FF9C
Master Bathroom Sensor: Parsing message: read attr - raw: 1D970104050A0000219CFF, dni: 1D97, endpoint: 01, cluster: 0405, size: 0A, attrId: 0000, encoding: 21, command: 0A, value: 9CFF
Have you seen this?