That is common with Flying dragon. I have 40+ citrus tree grafted on FD. Plus I have a very large Cara Cara Navel orange tree and a Large Marisol Clementine grafted on FD, which begun showing benching at a young age between the scion and the Flying Dragon rootstock. It has never been any concern at all. Good compatibility when grafted upon Flying Dragon has been reported with oranges and grapefruit. I have heard that some incompatibility could possibility show up on mandarins grafted on FD in 2 or 3 decades years, but how true this is I really don't know. Eureka Lemon is NOT compatible with Trifoliate Orange root stocks. - Millet