There are a couple of things to answer here, I’ll do my best.
-If you’re using Shadow Leap Kick as an Ender, and it’s being broken, it means the combo you performed was Opener>Ender. You need to make sure to throw in an auto double, manual, or linker to prevent your ender from being breakable. If it’s being broken immediately as you said, this is probably why.
-If you’re using it as a shadow linker, it can be broken like any other shadow linker if the opponent correctly times 3 hits of it.
-Jago’s Shadow Endokuken cannot be broken because it’s a projectile. Only a few projectile moves in the game are breakable, and even then only under certain circumstances.