If you suggest, perhaps (you have not described what is strange ... with this flat), that the size of the knight could perhaps be large against the horse, I have heard and read several times, that horses ijn the middle age were significantky smaller than those today (like humans !).
Silmilarly to the peplum movies of the years '60's where uniforms from antiquity and middle age were brillant, all romans red, today all horse engraved and mounted are large and high, but actually truth is somewhat different ...
The analysis of a large quantity of equine bones buried in the United Kingdom over more than thirteen centuries, between 300 and 1650 of our era, has made it possible to demonstrate that medieval horses, even fighting ones, approached more of our modern ponies than the sport horses we know. (1m30 to 1m50 instead of 1m70 !)