Nashorn passing a function through bindings

FULL PRODUCT VERSION :
java version "1.8.0_102-ea"
Java(TM) SE Runtime Environment (build 1.8.0_102-ea-b04)
Java HotSpot(TM) 64-Bit Server VM (build 25.102-b04, mixed mode)
---and---
openjdk version "9-internal"
OpenJDK Runtime Environment (build 9-internal+0-2016-04-14-195246.buildd.src)
OpenJDK 64-Bit Server VM (build 9-internal+0-2016-04-14-195246.buildd.src, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux <name> 4.4.0-51-generic #72-Ubuntu SMP Thu Nov 24 18:29:54 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
When calling a java function within JS it is not possible to work in different scopes (global/engine).


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
As example: https://gist.githubusercontent.com/MisterErwin/afb02ed9ab7f3e3ce39af3e82f10c3f0/raw/82bc1db3d06272a47ff463fcf3cbade55cdb2866/Foo.java

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Calling a function with and without a JS "Proxy-Function" should work
ACTUAL -
The java.lang.ClassCastException as seen in the error field

ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.lang.ClassCastException: Cannot cast jdk.nashorn.api.scripting.ScriptObjectMirror to java.util.function.Function
at java.lang.invoke.MethodHandleImpl.newClassCastException(MethodHandleImpl.java:361)
at java.lang.invoke.MethodHandleImpl.castReference(MethodHandleImpl.java:356)
at jdk.nashorn.internal.scripts.Script$Recompilation$7$17A$\^eval\_.proxy(<eval>:1)
at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:639)
at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:494)
at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:393)
at jdk.nashorn.api.scripting.ScriptObjectMirror.call(ScriptObjectMirror.java:117)
at jdk.nashorn.internal.scripts.Script$Recompilation$6$20$\^eval\_.withProxy(<eval>:1)
at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:637)
at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:494)
at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:393)
at jdk.nashorn.api.scripting.ScriptObjectMirror.callMember(ScriptObjectMirror.java:199)
at jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl(NashornScriptEngine.java:383)
at jdk.nashorn.api.scripting.NashornScriptEngine.invokeFunction(NashornScriptEngine.java:190)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

engine.eval("function proxy(a){return Java.type('Foo').bar(a);}",engine.getBindings(ScriptContext.GLOBAL_SCOPE));
engine.eval("function withoutProxy(){return Java.type('Foo').bar(m);}",engine.getBindings(ScriptContext.ENGINE_SCOPE));
engine.eval("function withProxy(){return proxy(m);}", engine.getBindings(ScriptContext.ENGINE_SCOPE));

engine.invokeFunction("withoutProxy"); //Works
engine.invokeFunction("withProxy"); //ClassCastException

(https://gist.githubusercontent.com/MisterErwin/afb02ed9ab7f3e3ce39af3e82f10c3f0/raw/82bc1db3d06272a47ff463fcf3cbade55cdb2866/Foo.java)
---------- END SOURCE ----------