A strange case, but are there others?
Yozan Mosig, a psychology professor, in 2012 wrote and published a paper that declared that the famous battle of Zama that ended Hannibal's successful career and signed Carthage's fate never occurred but was made up by Scipio, the supposed victor. The ending of the 2nd Punic War was he suggested a negotiated affair with no deciding battle.
The Romans had never beaten Hannibal and this was their revenge on Hannibal who had destroyed so many Roman armies, including of course his famous destruction of an entire Roman army at Cannae.
By claiming a victory, Scipio avoided embezzlement charges, and won himself fame and riches.
The actual battlefield has never been identified, nor did the Romans mark it with a monument.
What if history itself is just a long clever story constructed to deceive us? Anglo-Saxons never invaded Britain (many historians think they didn't), the Mongols gave gold to people to carry stories of their military might, the ancient Assyrians were merely merchants frightening whole peoples into giving them a good deal, the Golden Horde in Russia were just Asian kids out for a good time?
What in history could be fabrication?