why java decompiler does not show the correct code with lambdas?

I have this simple kotlin class:

class MyClass {

    private val x: Int = 10
    val m: (Int) -> Int = { a: Int ->
        a*a + a
    }
}

and I used the IntelliJ decompiler and this is the java code:

public final class MyClass {
    private final int x = 10;
    @NotNull
    private final Function1 m;

    @NotNull
    public final Function1 getM() {
        return this.m;
    }

    public MyClass() {
        this.m = (Function1)null.INSTANCE;
    }
}

as you can see there is no sign of what's placed in the lambda argument m which is a*a + a in the java code and it always returns a null value for m. however, there exists a bytecode for that code:

public final invoke(I)I
    // annotable parameter count: 1 (visible)
    // annotable parameter count: 1 (invisible)
   L0
    LINENUMBER 7 L0
    ILOAD 1
    ILOAD 1
    IMUL
    ILOAD 1
    IADD
   L1
    IRETURN
   L2

I guess this is a problem with decompiler right? if so what decompiler should I use?