Here is a useful account of the battle of Humbleton or Homildon Hill in 1402, with substantial material from Thomas Walsingham (d. c. 1422) giving the English view of the battle, and from Walter Bower’s Scotichronicon, written in the 1440s, more than a generation after the battle, describing the combat from a Scottish viewpoint.
Giving due allowance for the biases in the different accounts, this is what I think actually happened. A Scots army under the Earl of Douglas was returning from a raid into Northumbria when it found a large English army blocking its way home. The English army was about 50% larger. The Scots army took up a defensive position on the slopes of Humbleton hill. The English initially deployed across the road back to Scotland, but then put archers on “a hill facing the Scots”
In the ensuing firefight, the Scots were at a considerable disadvantage. Not only was their force outnumbered, but English armies tended to include a large proportion of archers: Scottish armies tended to have fewer. Further, English archers had a very high reputation for individual strength and skill: Scots archers less so. Walsingham reports that the Scottish archers fled from the storm of arrows. Bower, without mentioning Scottish archers, says that the Scots were smothered by a rain of arrows, and many were killed and wounded. Presumably the Scots archers and other lightly armored troops suffered most of the casualties.
As the most vulnerable Scots began to duck and retreat from the English arrows, a fraction of the Scottish men-at-arms charged the English. Bower claims that a hundred knights charged the English, “contended intrepidly with a thousand English” and were all slain, but “not without great slaughter of the English”.
Walsingham, on the other hand, reports that no English “lord or knight received a blow from the enemy” and that they “remained idle spectators of the battle”.
The two accounts aren’t necessarily contradictory. It’s plausible that the bravest Scottish men-at-arms made a mounted charge against the English archers. Some of the Scots would have been wounded or dismounted, but enough probably survived to charge home: that was the normal pattern of attacks by fully armored men at arms against English bowmen. At Agincourt the archers were protected by stakes, but this tactical innovation does not seem to have been used at the earlier battle.
Once the Scots closed to handstrokes, the survivors were confronted with a group of English archers that outnumbered them substantially: by ten to one or more, according to Bower. Further, the Scots would have been disordered by casualties suffered as they closed. Under these conditions a man at arms in superior harness could be overwhelmed by a host of individually inferior opponents. If the Scottish knights fought stubbornly, as Bower reports, they could have inflicted significant casualties on the lightly protected archers before they were themselves overwhelmed.
Unsurprisingly, both Chroniclers omit information that would create a less favorable impression of their side’s performance. Bower doesn’t mention what sort of troops the Scottish knights attacked: “great slaughter” inflicted on lightly armed archers is less impressive than do the same to men-at-arms. Walsingham passes over casualties suffered by the English archers in hand to hand combat