In Mark 2:18 and Luke 5:33 σοι is tagged by Logos as a second person nominative plural. As well, when in Bible Word Study when you look at the Morphology Charts, it lists σοι as such and σῷ as dative singular.
This is not a mistake. If you look closely, you will see that the lemma for the words you noticed is σός, the possessive adjective, not σύ, the personal pronoun.
Well, look at that. First time I was wrong today. 😊 Thank you Robert!
