http://www.pogo.org/blog/2015/04/gao-confirms-increased-f-35.html
http://aviationweek.com/defense/controversy-flares-over-f-35-air-combat-report
http://www.businessinsider.com/here-are-all-the-problems-with-the-f-35-that-the-pentagon-found-in-a-2014-report-2015-3
http://www.gao.gov/assets/670/661842.pdf
http://www.gao.gov/products/GAO-15-364
You must have just started paying attention to military weapons system development. They all have teething problems. With modern oversight any knownothing can read the problem reports and conclude stuff. If you want to go back in time you can find articles like that about every major (and minor) weapons system. If they naysayers had their way our military would be wearing furs and using clubs.