Returning from injury, Dunk was caught in two minds at the back which allowed Aleksandar Mitrovic to swoop in and score the visitors second goal of the day.
Ryan said: "Everyone's human. It's unfortunate it had to happen on his return. He'll learn from it. Being born and bred here he feels every moment for the club, good and bad.
"He's in good spirits. He'll learn from that situation and I'm sure it won't happen again."