Hey @techspace ,
welcome to the Quick Sight Community! 
It seems to be a known bug: Quicksight dividing latitude and longitude values by 1000 - Question & Answer - Amazon Quick Sight Community. There was also a community post a couple of weeks ago that mentioned a similar problem, sadly I can’t find it.
But if you need a workaround maybe @ErikG solution in the linked post can help you.
BR
Robert