Hi Paul, Thank you very much for reporting this issue. I confirm this happens when purging the package only. The offending chown was first introduced in the tomcat6 package 6 years ago [1] as part of the fix for #567548. The same issue is also found in the tomcat7 package.
Do you think running something like "chmod -R 640 /etc/tomcat8" right before the chown is an appropriate solution to this issue? Emmanuel Bourg [1] https://anonscm.debian.org/cgit/pkg-java/tomcat6.git/commit/?id=f67781f
