Unreasonable training time when I make a simple change

[LuisGPMa]

So I am training a CHAID decision tree for multiclass classification, and the target variable is a string. Other than the target, I have 4 other features, two of which I want to be string type. When I train the model with only one feature as string, training takes about 15 minutes. But when I convert the other feature I wish to be treated as categorical to string, training takes forever (entire day and no result).

What could be causing this?

[serengil]

can you share the data set?

[LuisGPMa]

Unfortunately I can't, sorry.

[serengil]

so, i cannot resolve your problem