I see a few:

On The Wedding Feast at Cana, black guy in green sitting at the leftmost table speaking (or about to kiss) a guy coming from behind the pillars

On The Feat in the House of Levi, two guys near the fourth pillar from the left behind the black man in black (yellow shirt and green shirt), another black guy in red at almost exactly the same spot from the other side

they're not yelling or anything but pretty sure their mouths aren't shut