StackMapTable error: bad offset

[psibi]

Following is the code:

stack1Class :: ClassFile
stack1Class =
  mkClassFile
    java8
    []
    "Stack1"
    Nothing
    []
    []
    [ mkMethodDef
        "Stack1"
        [Public, Static]
        "main"
        [arr . obj $ "java/lang/String"]
        void $
      fold
        [ iconst jint 3
        , gstore jint 1
        , gload jint 1
        , iconst jint 2
        , if_icmpne
            (fold $
             [ getstatic systemOut
             , bipush jint 42
             , invokevirtual printlnI
             , vreturn
             ])
            (fold $
             [ getstatic systemOut
             , bipush jint 43
             , invokevirtual printlnI
             , vreturn
             ])
        ]
    ]
  where
    systemOut = mkFieldRef "java/lang/System" "out" (obj "java/io/PrintStream")
    printlnI = mkMethodRef "java/io/PrintStream" "println" [prim JInt] void

On execution of the class file it generates, it will give this error:

@sibi::jane { ~/github/codec-jvm }-> java Stack1
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.VerifyError: StackMapTable error: bad offset
Exception Details:
  Location:
    Stack1.main([Ljava/lang/String;)V @0: iconst_3
  Reason:
    Invalid stackmap specification.
  Current Frame:
    bci: @25
    flags: { }
    locals: { '[Ljava/lang/String;', integer }
    stack: { }
  Bytecode:
    0x0000000: 063c 1b05 a000 0cb2 0007 102b b600 0fb1
    0x0000010: b200 0710 2ab6 000f b1
  Stackmap Table:
    append_frame(@16,Integer)
    same_frame(@25)

        at java.lang.Class.getDeclaredMethods0(Native Method)
        at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
        at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
        at java.lang.Class.getMethod0(Class.java:3018)
        at java.lang.Class.getMethod(Class.java:1784)
        at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
        at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)

This is the bytecode generated for the main method (which to my naive eyes appear valid):

    Code:
      stack=2, locals=2, args_size=1
         0: iconst_3
         1: istore_1
         2: iload_1
         3: iconst_2
         4: if_icmpne     16
         7: getstatic     #7                  // Field java/lang/System.out:Ljava/io/PrintStream;
        10: bipush        43
        12: invokevirtual #15                 // Method java/io/PrintStream.println:(I)V
        15: return
        16: getstatic     #7                  // Field java/lang/System.out:Ljava/io/PrintStream;
        19: bipush        42
        21: invokevirtual #15                 // Method java/io/PrintStream.println:(I)V
        24: return

Replace return in bci 15 with a goto solves the problem. But I think the above instruction should also work.