I couldn’t find an actual article about this, but very cool find from the folks at Retro-Sheet:

Although it was not actually a case of batting out of turn, the Red Sox had an amazing mistake in the 9th inning of their 16-3 loss to Baltimore on August 25, 2017. As is often the custom in such lopsided contests, the Red Sox put a position player on the mound in the top of the 9th. In this case, it was Mitch Moreland, who had played first base the entire game to this point. The Red Sox lost the DH for the remainder of the game and the new first baseman, Hanley Ramirez, entered the game in the 7th spot in the batting order, formerly occupied by DH Chris Young. They made no other changes. Moreland did well in his one inning as pitcher, allowing no runs on two hits and even collecting a strikeout.

The trouble occurred in the home 9th. The first batter was Rafael Devers, batting in the 6th spot. He made an out and the proper next batter was Ramirez. However, Chris Young came to the plate and singled – even though he was no longer in the game! This is the only case of illegal lineup reentry in Major League history. No one appeared to notice – not the umpires or either team. Since it was a 16-3 game with two outs to go, it is likely that Ramirez had not even thought about where he was batting. As for DH Young, he simply followed Devers to the plate as he had all night. The official remedy is to call Young a pinch-hitter for Ramirez, which causes all the official totals to come out right.