There was a forgery of the Palestinian Talmud

FAKE TALMUD: The Forged Yerushalmi: A 20th-Century Controversy. Revel’s 80th Anniversary Lecture Series Features Discussion of Famous Talmudic Forgery (Yeshiva University News). The lecture was by "historian Rabbi Boruch Oberlander, head of the Budapest Orthodox Beis Din and a long-time leader in the Hungarian Jewish community."

The discussion revolved around one of the most famous recent forgeries of a sacred Judaic text. In January 1907, Shlomo Yehuda Algazi-Friedländer published in Hungary what he claimed were the long-lost tractates of Seder Kodashim of the Jerusalem Talmud, garnering praise in rabbinic circles for bringing this material to light.

I didn't know about this one. The forgery was detected and within months and thoroughly debunked by 1913, so it doesn't seem to have been very good.