They did not recognize feeding the thousands to be Miraculous

Mark 6:45 And straightway he constrained his disciples to get into the ship, and to go to the other side before unto Bethsaida, while he sent away the people. 46 And when he had sent them away, he departed into a mountain to pray. 47 And when even was come, the ship was in the midst of the sea, and he alone on the land. 48 And he saw them toiling in rowing; for the wind was contrary unto them: and about the fourth watch of the night he cometh unto them, walking upon the sea, and would have passed by them. 49 But when they saw him walking upon the sea, they supposed it had been a spirit, and cried out: 50 for they all saw him, and were troubled. And immediately he talked with them, and saith unto them, Be of good cheer: it is I; be not afraid. 51 And he went up unto them into the ship; and the wind ceased: and they were sore amazed in themselves beyond measure, and wondered. 52 For they considered not the miracle of the loaves: for their heart was hardened.
53 And when they had passed over, they came into the land of Gennesaret, and drew to the shore. 54 And when they were come out of the ship, straightway they knew him, 55 and ran through that whole region round about, and began to carry about in beds those that were sick, where they heard he was. 56 And whithersoever he entered, into villages, or cities, or country, they laid the sick in the streets, and besought him that they might touch if it were but the border of his garment: and as many as touched him were made whole.