Thank you for checking, that issue will be one of the good reasons that the project I'm in charge of should move to the new version.
In my particular case, our project has been originally planned and tested against v5.4 and won't use Dashboard feature even if upgraded to v6.
Is it safe not to create, or to delete BAMTaskSummary and OrganizationalEntity records in the case if Dashboard isn't used ?
One idea would be to negate BAMTaskEventListener by vetoing the class by ProcessAnnotatedType lifecycle event.