I bought 2 of these  as was impressed with the first one the second one stays at the temp it finds on install in the last case 60deg C!! and Humid is 60% and no its not located in the sauna!

I have deleted it and reinstalled it at least 6 times but still gives a reading that never changes from a random temp it found on installation I have breathed on it as per one sergestion placed it on a pack of frozen peas  the peas defrosted but the temp humid never changed! The first one I bought i have placed it next to the suspect one and it tracked perfectly the second just sits there at a fixed temp......any ideas please!