cause the rap superstar switched up his song lyrics to ... a rift are there -- Drake unfollowed him on social media ... and he took apparent shots in his "Fighting Irish Freestyle" song.

Since 2013, they have both released multiple diss tracks against one another, including Drake's First Person Shooter and Taylor Made Freestyle, and Kendrick's Euphoria, Meet the Grahams ...

During the performance of “euphoria,” Kendrick, 37, revealed some new lyrics, referencing a ring that Tupac Shakur owned that Drake ... rapper on “Taylor Made Freestyle,” which was ...