The 2022 champions saw their title slip away in New Jersey as Ferran Torres scored an extra time winner to seal a 1-0 victory for Luis de la Fuente's team at the MetLife Stadium.
However, the post-match celebrations were marred by several violent scuffles between players from both sides, which were picked up by TV cameras and shared across social media in the aftermath.
Argentina midfielder Leandro Paredes is at the centre of the row, after he appeared to strike Spain star Gavi to the ground, alongside an allegation of Nahuel Molina punching La Roja captain Rodri.
FIFA have since confirmed an investigation has been started into the incident with a disciplinary and ethics prosecutor now appointed to review the referee's report and post-match video footage.
It was also confirmed reports of Paredes being shown a red card during the melee are inaccurate, so there's no instant suspension for the Boca Juniors star, but he will likely face questions in the coming weeks.
FIFA have not offered a time scale on that review, or the possible punishments for Argentina, with Lionel Scaloni's team yet to confirm their match plans for September's international break.