Here's a clip of the play in question. As you can see, the outfield wall at Kauffman Stadium is all bright lights, ads and scores of other games. The two outfielders went for the ball and it dropped between them. The view from first wasn't that great but Hernandez shouldn't have made the call if he wasn't sure.
Angel Hernandez is one of the worst if not the worst umpires in baseball. It’s between him and Joe West. But on watching this, if Hernandez is on first base I did not see him signal at all nor did any of the umps. Maybe it is the angle I saw.