I'm not replicating the success you're getting, but I think that's because I have a bigger problem.
Using the default regex to test in the test tool in Adding Books, I'm not even getting the right response for a basic
Code:
(?P<title>.+) - (?P<author>[^_]+)
Test Title - Test Author
gives me
Title: No match
Authors: Unknown
I tried uninstalling/reinstalling the application, but that didn't help.
Any ideas about this? Is something corrupt?