On behalf of Xerces-J XML Schema team, I would like to thank folks from Oxygen XML team to highlight many important bugs within Xerces-J XSD 1.1 validator. We've been able to solve many of those reported bugs, and I feel this has made implementation of Xerces-J XSD 1.1 validator quite better.
Here's the list of issues reported by Oxygen folks during the past 1-2 years I guess, which are either resolved or closed:
https://issues.apache.org/jira/issues/?jql=project%20%3D%20XERCESJ%20AND%20issuetype%20%3D%20Bug%20AND%20status%20in%20%28Resolved%2C%20Closed%29%20AND%20reporter%20in%20%28radu_coravu%2C%20%22octavian.nadolu%22%29
In the above report, you might ignore bugs dated as old as 2006, which must have been resolved within an existing or an earlier Xerces-J version.
Other than the bugs reported by Oxygen XML folks, we also received bug reports from other members of XML community. Thanks to those persons also.
I'm not sure when we're going to release next version of Xerces-J which should have many implementation improvements. Taking a very pessimistic view wrt this, I expect a new version of Xerces-J sometime later this year or might slip to next year.