Thanks for testing and finding the bug! I'm not involved with the project but
did find this on the author's website:

"You can submit bug reports and feature requests, and view the list of known
bugs, at the REXML bug report page. Please do submit bug reports. If you really
want your bug fixed fast, include an runit or Test::Unit method (or methods)
that illustrates the problem. At the very least, send me some XML that REXML
doesn't process properly.

You don't have to send an entire test suite -- just the unit test methods. If
you don't send me a unit test, I'll have to write one myself, which will mean
that your bug will take longer to fix.

When submitting bug reports, please include the version of Ruby and of REXML
that you're using, and the operating system you're running on. Just run: ruby
-vrrexml/rexml -e 'p REXML::Version,PLATFORM' and paste the results in your bug
report."