Same. Since the beginning. It happens when surprising enemies A LOT. Not just shared initiative.
And I've also noticed it will skip a character's turn and have enemies go who are after their initiatives, then bounce back later to the skipped character's turn.
So Gale was third in order. 3 goblins came after him then Astarion. Gale got skipped, the 3 gobbos went, then Gale, then Astarion. ??? That's messed up.