Hello,
My friend was on OPT in 2008. F-1 less than 5 years (Masters 2 years, OPT 1 year). So he submitted 1040NREZ in 2009 for filing taxes... The IRS converted it into 1040EZ saying OPT is not considered as non-resident status. He was also sent a stimulus check last mont with this comment letter. I am literally confused... I researched for documentation on IRS... no luck. Any comments.
Thanks.

In this case, the IRS is flat out WRONG!

Optional Practical Training IS considered part of the F-1 student visa; has been for decades.