U.S. runner Paul Chelimo thought he was giving an interview in recognition of his earning the 5,000m silver medal behind Great Britain’s Mo Farah. Instead, he was informed on live television by NBC’s Lewis Johnson that he had been disqualified for “infringement of the inside border.”
...
Chelimo filed an appeal, which was approved; his silver medal was reinstated. 41-year-old fellow American Bernard Lagat had been in line to earn the bronze, but found himself bumped off the podium again.

http://deadspin.com/paul-chielmo-earns-silver-in-5-000m-learns-he-was-disq-1785552478

Besides Chelimo, Mohammed Ahmed of Canada and Muktar Edris of Ethiopia were also disqualified. Ahmed, too, was later reinstated, putting him back in fourth place.

Edris remained disqualified, but Ethiopian teammate Hagos Gebrhiwet ended up with bronze after being briefly upgraded to silver.

http://www.stuff.co.nz/sport/olympics/83405277/rio-olympics-2016-in-the-end-american-runner-paul-chelimo-got-his-5000m-silver-medal