Hi! If you look really closely at the format of the input data, you can see that it somehow ended up with some strange markup in the keys – I wonder if something went wrong when you saved/converted the data? For example, the key ends up being "[{\"text": ... and the whole JSON was saved out as a string key, instead of as JSON.
So the error happens because the format isn't a dictionary with the key "text" and Prodigy doesn't know what to load.