The event-shared-deploy pom.xml parent <artifactId> is listed as "db-base". Its true parent is "event-base".

<?xml version="1.0"?>
<project xmlns="http://maven.apache.org/POM/4.0.0">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>db-base</artifactId>
<groupId>org.sakaiproject</groupId>
<version>2.5.2</version>
<relativePath>../pom.xml</relativePath>
</parent>
<description>Shared Deployment Descriptor for Event</description>
<name>sakai-event-shared-deploy</name>
<groupId>org.sakaiproject</groupId>
<artifactId>sakai-event-shared-deploy</artifactId>
. . .
</project>