So-called universal outlets can't get the polarity right for all countries, because all countries are not consistent. However, IEC inputs ARE consistent in polarity, if not voltage. Assuming, of course, that the IEC input cords are wired correctly, which they occasionally aren't.
So yes, when you're using a US plug, you're getting hot and neutral swapped. Which could be dangerous with some devices. If you're never going to travel internationally with this device, I'd suggest correcting it.