Also, people figured out the Earth was round long ago exactly because of these sorts of discrepancies.

Sure, they had an understanding of how the thing warped, they could see with their own eyes that their flat math was kinda rubbery with curved surfaces, but they hadn't separated the two realms of geometry, hadn't figured out that you could have a triangle where the angles didn't add up to 180°.

It must have been very strange and disturbing to see math as imperfect, incomplete or mischievous in some way. Wasn't this the language of God? Therefore, shouldn't his language be perfect?

While this might be going on in your mapmaking mind, the king or emperor, the generals and admirals, and the religious authorities are looking closely at these maps, and here you are making something that has a hazy sense of sacrilege.