See your code examples it looks like bug.
Pairs works but not syllables.
import hyphen
h = hyphen.Hyphenator('pl_PL', 0, 0, 0, 0)
# CVCVCCV - Vowel, Consonant
h.pairs('Maryśce')
# [['Ma', 'ryśce'], ['Mary', 'śce'], ['Maryś', 'ce']]
# Syllables not works
h.syllables('Maryśce')
# ['Ma', 'ry', 'ś', 'ce']
# ś is consonant in Polish must be one vowel in syllable.
Valid is just Ma-ry-śce or Ma-ryś-ce.
See your code examples it looks like bug.
Pairs works but not syllables.
Valid is just Ma-ry-śce or Ma-ryś-ce.