Double parameter set

Hi all

I wonder if any can explain me why Dynamo gives me double parameters?
If I use category-all elements of category – element parameter, then Dynamo gives me a uniq set of parameters + values

If I use family type – all elements of family type- element parameter, then Dynamo gives me a list of parameters + values, where some of them are double
If I change the family types is to another selection, then I am given a similar result but the double set is different, if I then change the family types back to the first, then it is would be some other parameters + values that is double, then the first selection.

Any explanation?