Deep Learning Tutorial - Python Recipe Time Series

I'm not sure if it is due to my computer, but I followed the time series deep learning tutorial which is amazing and ran into problems where the python recipe to provide 31 array is sent to the LSTM, puts random "?" characters in the datasheet which crashes the deep learning session when it tries to convert it from a string to float. Once I used prepare to remove the "?" the deep learning seems to work out fine.

"?" didn't exist in the original datasheet or temperatures_prepared.