Fix is to delay the extra join added via BeanPropertyAssocOne until after the children nodes have joined.

In this way the join is ONLY added if not already done so via a child node (SqlTreeNode).

ebean-core/src/main/java/io/ebeaninternal/server/query/SqlTreeJoin.java

@@ -0,0 +1,2 @@
+package io.ebeaninternal.server.query;public interface SqlTreeJoin {
+}