Ask HN: Why does AI-generated text often don't have a space after a period?

I'm a bit surprised that many AI-text generation tools are capable of generating the output they do, while still quite frequently not adding a space before the first letter of a new sentence. I find it even more puzzling that most of the time they do, but sometimes they don't.Kinda like I do here in this paragraph. It seems like a comparatively very simple issue to fix.