As noted yesterday, The Wrestling Observer Newsletter reported a backstage fight took place between Sheamus and Sin Cara, who is played by Jorge Arias, who also portrays Hunico.
WZ has reached out to sources within WWE and learned this fight did not take place this past week at television tapings as the original report is claiming. The altercation actually took place a few weeks ago, and it's unclear why news of the fight is just now surfacing, and why it was reported as happening this week.
Sources have verified, however, that an altercation did indeed take place, and if the fight had not been broken up, it could have gotten really bad for Sheamus.
The word backstage is the two have made some peace and there have been no issues since.