If I were to re-learn the rules, I could probably point it out. The best I recall is we were skipping a small step in the turn cycle.

Maybe it was upkeep-related? There's the phrase "untap, upkeep, draw" and all the "at the beginning of your next turn" cards refer to the upkeep phase if I'm not mistaken, maybe putting upkeep before untap or after draw would lead to some weird long-term mechanics.