I don't know if matters have improved any, but back when I created my lemmy.world account specifically it had some kind of bugout about what I'd entered, but it output this to the developer console and not on the page itself. Had I not thought to press F12 I would not have discovered that it had its panties in a twist about whatever it was, I think characters in my email address or something. I forget exactly what its problem was.
So yeah, I can definitely seeing that baffling the average user.