As described in summery we have a leak that prevents tomcat shutdown. Older MyCoRe-Versions doesn't have this problem. I tested it with "MyCoRe 2018.06.0-SNAPSHOT 2018.06.0.x:v2018.05-48-g102e24b" and this version shuts down clean.
So we have to look into the changes after this commit 102e24b.
Perhaps changes for are the reason for this problem?