NullPointerException in BeanDescriptor.contextGet(BeanDescriptor.java:1701)

[risenhoover]

I am upgrading to ebean 15.1.0 from an old version of the playintech ebean fork. After the upgrade, I am seeing a significant number of intermittent NullPointerExceptions. Here is a typical stack trace:

Caused by: java.lang.NullPointerException: null
	at io.ebeaninternal.server.deploy.BeanDescriptor.contextGet(BeanDescriptor.java:1701)
	at io.ebeaninternal.server.deploy.BeanDescriptor.createReference(BeanDescriptor.java:1481)
	at io.ebeaninternal.server.deploy.BeanDescriptorCacheHelp.manyPropLoad(BeanDescriptorCacheHelp.java:283)
	at io.ebeaninternal.server.deploy.BeanDescriptor.cacheManyPropLoad(BeanDescriptor.java:939)
	at io.ebeaninternal.server.core.DefaultBeanLoader.loadManyInternal(DefaultBeanLoader.java:75)
	at io.ebeaninternal.server.core.DefaultBeanLoader.loadMany(DefaultBeanLoader.java:42)
	at io.ebeaninternal.server.core.DefaultServer.loadMany(DefaultServer.java:443)
	at io.ebean.common.AbstractBeanCollection.lazyLoadCollection(AbstractBeanCollection.java:90)
	at io.ebean.common.BeanList.init(BeanList.java:136)
	at io.ebean.common.BeanList.isEmpty(BeanList.java:316)
	at models.X.getY(X.java:867)

The actual code is quite simplistic and there is in fact a check for a null prior to the call that is generating the exception:

public X getY() {
    if (this.getInsiderForm().getInsiderFormInsiders() != null
        && !this.getInsiderForm().getInsiderFormInsiders().isEmpty()) {  // this is the line 867 generating the exception
      return this.getInsiderForm().getInsiderFormInsiders().iterator().next();
    }
    return null;
 }

I have reviewed the https://ebean.io/docs/trouble-shooting page for common errors but it doesn't seem like this fits any. I have stepped through the code but am unfamiliar with ebean internals. Any advice would be appreciated.

[risenhoover]

Currently testing a theory that a mapping may be faulty.