I was an F1 student in the USA till Sept 2014. Then I had a job offer in S. America that started in Jan 2015 (so I am living in S. America now). As soon as I graduated in Sept, my major program switched my status to 'Research Scientist'. So I continued working at the same university from Sept-Dec 2014 in an OPT. So my re-stamped I20 (and of course the OPT card) is valid till Sept 2015. My F1 visa won't actually expire till 2016.
Now, I want to visit my friends in the USA next month (April 2015). In this case, would I have any problems at the port of entry with the immigration officers?
My only concern is that, though my travel documents haven't expired, the university might have put a note such as 'this person is no longer working with us', which could have terminated the validity of my I20, and there's no way of knowing this.