Sorry for the late response.
This bug was a major annoyance, so I re-installed a fresh copy of 13.04 a couple of weeks after filing the bug and everything works ok again.
If there's a way I can provide more info without re-upgrading to 13.10 (thus risking to make the system unusable again) I'd be happy to help.
Thanks for your feedback anyway
Sorry for the late response.
This bug was a major annoyance, so I re-installed a fresh copy of 13.04 a couple of weeks after filing the bug and everything works ok again.
If there's a way I can provide more info without re-upgrading to 13.10 (thus risking to make the system unusable again) I'd be happy to help.
Thanks for your feedback anyway