Double stack traces with rewrite.java.trace enabled

I was looking at an example for the rewrite.java.trace:

The example command is:

jruby -Xrewrite.java.trace=true -X-C run_blah.rb

This works great. However if I do not disable compilation (using the
-X-C option) then the stack trace is duplicated. Check out this forked
gist:

In it the stack trace reported is repeating lines:

from java/lang/reflect/Method.java:606:in invoke' from run_blah.rb:6:in bar’
from run_blah.rb:6:in bar' from run_blah.rb:2:in foo’
from run_blah.rb:2:in foo' from run_blah.rb:9:in (root)’
from run_blah.rb:9:in `(root)’

Does anyone know why the stack trace is double printing?

Thanks in advance,

Peter