This is actually frustratingly common with off-the-shelf ERP 'integrations'. Things like courier labelling software come to mind as culprits. And you are stuck between trying to get UPS to fix a system that they give away free, or training sales operators to write addresses properly.

I love the ones that present a REST api but still can't handle commas, because they have wrapped some ancient importer in a front end that simply writes the request data to a csv! I had to write one once, but I double quoted all fields and had to translate UTF-8 back to some other standard the old ERP used! It was junk, but I believe is still chugging away years later...