which means that most of the suffixes exist in two different forms -one with a front vowel and another one with a back vowel -and it is the vowels within the stem that determine which form of the suffix is attached to the word.
the codes Nc-sd and Nc-sd---s3 will be reduced to the same form since there is no such Hungarian lemma that would have the same word form for a dative singular and a dative singular with a third person singular possessor (and thus, the POS-tagger would not have to choose between these possibilities).