GString not converted to String in some cases

The following groovy snippet results in an exception because the GString is not automatically converted into a String:

stringList = ["US-ASCII", "UTF-8", "UTF-16"].each {
"test".getBytes("$

")
}

I had a difficult time getting this down to a simple test case. It appears that this is only a problem when you're using an overloaded method (like getBytes()). This same test will work fine with concat().