Rule 101 for small stakes (maybe even all) poker; WHEN IN DOUBT, BET/FOLD.
This is a very good rule for PLO, since preventing an opponent realising his equity is so very important. However, it does not apply quite as strongly to other poker variants, NLHE included.
However, in this case it does apply. Which means that:
Don't check the turn back either, clear bet imo.
Is completely right.