Welcome to the Q&A Forum

Hi! Sorry to see only now this question. I've experienced this issue once and resulted that it was due to the hl=X cookie and the fact that the cookie. I suggest you check if it's also your case.

Not knowing the site, the answer here will be quite generic. Said that, let's start from the misguided concept of Latin-America. Latin America actually really doesn't exist. If you tell to a mexican and argentinian they have practically the same culture or speak the same language, they will laugh at you. Seriously, the biggest error when targeting those countries, which include a not spanish speaking country as it Brasil, is considering them as they were a consistent set of nations. Said that, in your case, if you have the resources or the time to localize every single page of your site for all the countries, then you should have a site targeting all the spanish speaking language of Northern, Central and South America. In fact, doing some pages as common and some other localized in a subfolder, can lead to a bad user experience, because they should always shifting from a generic not targeted page to the targeted one. But on the long term, and basing the choice on from where the highest organic traffic is coming, I would start preparing and publishing the localized versions for each country. In order to avoid potential duplicated or substantially duplicated content you can use the rel="alternate" hreflang="x-X" markup, so to tell Google to show - for instance - the /mx/... URLs just to the users searching from Mexico and the /ar/... URLs only to the Argentinians searching in Google.com.ar. Obviously, you will have also to geotarget the folder in GWT and earn local links in order to reinforce the geotargeting of your subfolder.s