reset_index() error after crosstab
Hi All,

I have a pandas dataframe which I constructed after doing a crosstab. When I try to `reset_index()` it gives me an error. Saying `TypeError: cannot insert an item into a CategoricalIndex that is not already an existing category` this happens sometimes and does not happen sometimes. The pandas dataframe was constructed using dask `.compute()` method.

Would anyone be able to tell me what is the issue and how to rectify it. I have `pandas 0.24.2 ` running. 

Thanks

Michael