GenericDelegator's findByAnd which is invoked in the midst of group deletion for permissions and notifications removal does not distinguish the case-sensitivity of the parameter, provided that the JIRA is running on top of MySQL, e.g.

ManagerFactory.getPermissionManager().removeGroupPermissions(group.getName());
-> ManagerFactory.getPermissionSchemeManager().removeEntities(group);
-> -> CoreFactory.getGenericDelegator().findByAnd(getEntityName(), EasyMap.build("parameter", parameter));

This produces malfunction to the process, i.e. schemes of another group will be deleted instead.