Is it possible to receive Luck Up collecting a coin?
When donating for the first time to the Greed Machine after beating Ultra Greed, you unlock the Lucky Pennies achievement. This achievement grants a small chance of replacing the normal pennies with a version that gives Luck Up when you pick them up, that's what's giving you the effect.
Jeah, they seemed to have added a chance for a luck up from picking up pennies. Might be related to some kind of "lucky penny". Had that effect a few times now in different runs with different items and different characters, so I am pretty sure that it is not related to any item.