In previous articles I have covered what undesigned coincidences are and why they matter, and then several such undesigned coincidences in the retellings of the feeding of the 5000 - Here, and here, and also here. 

Here's yet another one from the same narrative. In a sermon at a different occasion, recorded in Matthew's Gospel, Jesus went hard at the unrepentant cities of Chorazin and Bethsaida. Matthew 11:21:

"Woe to you, Chorazin! Woe to you, Bethsaida! For if the mighty works done in you had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes."

But nowhere in Matthew is it mentioned directly that Jesus performed Miracles in or near these cities. But if we go to Luke, we will find that the feeding of the 5000 happened in Bethsaida, and that Jesus also healed people there.

Luke 9:10-17

"On their return the apostles told him all that they had done. And he took them and withdrew apart to a town called Bethsaida. When the crowds learned it, they followed him, and he welcomed them and spoke to them of the kingdom of God and cured those who had need of healing. Now the day began to wear away, and the twelve came and said to him, “Send the crowd away to go into the surrounding villages and countryside to find lodging and get provisions, for we are here in a desolate place.” But he said to them, “You give them something to eat.” They said, “We have no more than five loaves and two fish—unless we are to go and buy food for all these people.” For there were about five thousand men. And he said to his disciples, “Have them sit down in groups of about fifty each.” And they did so, and had them all sit down. And taking the five loaves and the two fish, he looked up to heaven and said a blessing over them. Then he broke the loaves and gave them to the disciples to set before the crowd. And they all ate and were satisfied. And what was left over was picked up, twelve baskets of broken pieces."

And if we look at the other Gospel's narratives of the same event, it's clear that the feeding miracle happened on the countryside, hence Bethsaida is used as a marker of the general area (although the healings may have taken place in town).

John 6:1

"After this Jesus went away to the other side of the Sea of Galilee, which is the Sea of Tiberias."

Mark 6:30-32

"The apostles returned to Jesus and told him all that they had done and taught. And he said to them, “Come away by yourselves to a desolate place and rest a while.” For many were coming and going, and they had no leisure even to eat. And they went away in the boat to a desolate place by themselves."

Matthew 6:13

"Now when Jesus heard this, he withdrew from there in a boat to a desolate place by himself. But when the crowds heard it, they followed him on foot from the towns"

So, we need to go from Matthew to Luke to get an explanation for that there really were miracles in the places Jesus referred to, and then from Luke to the other Gospels to see that Bethsaida is used as a regional marker, and that the feeding miracle happened on the countryside outside of Bethsaida, thus also placing it near the neighboring city Chorazin.

And thus, we have yet another undesigned coincidence related to the feeding of the 5000 miracle. There's simply too many of them to disregard them as coincidences. The feeding of the 5000 is a historical event. It happened.