In 5e, creatures get a new saving throw against most spells at the *end* of each of their turns. On a success, the spell's effect on them ends. Since it happens at the end of their turns, if they fail the initial save they're guaranteed to be confused for at least 1 turn.
BG3, however, has new saves happen at the *start* of creatures' turns. Thus, every creature gets 2 chances (effectively Advantage) to succeed on a spell before feeling its negative effects.
Additionally, there are various bugs in BG3 where failing the 2nd save STILL removes the condition from the creature, in what I assume is a "-1 x -1 = 1" situation. The game says "you failed, so toggle the confusion condition on your character" which toggles it from ON back to to OFF.
tl;dr: ST spells with durations in BG3 suck (except for maybe Hypnotic Pattern)
