Impacted versions:
9.0 Community & 9.0 Enterprise

Steps to reproduce:
- Open up a V9 runbot
- Go to projects and click on the issues item, for example for the project 'Research & Development':
  ![image](https://cloud.githubusercontent.com/assets/6352350/13873686/65f2c31c-ecf3-11e5-917a-38df2832bd00.png)
- The project tasks view is opened in place of the project issues. (notice that this only happens every once in a while, about once in five attempts) Example:
  ![image](https://cloud.githubusercontent.com/assets/6352350/13873789/14798b64-ecf4-11e5-9b77-f2ad5d3a8adc.png)

Current behavior:
Every once in a while (about one out of five attempts) after clicking on the issues button it will open up the project tasks, not the issues.

Expected behavior:
When you click on the issues the view with all issues opens, not the view for all tasks.

if project_id:
            project = self.pool.get('project.project').browse(cr, uid, project_id, context=context)
            if project and project.partner_id:
                return {'value': {'partner_id': project.partner_id.id}}
        return {}
    _columns = {
        'id': fields.integer('ID', readonly=True),
        'name': fields.char('Issue', required=True),
        'active': fields.boolean('Active', required=False),
        'create_date': fields.datetime('Creation Date', readonly=True, select=True),
        'write_date': fields.datetime('Update Date', readonly=True),
        'days_since_creation': fields.function(_compute_day, string='Days since creation date', \
                                               multi='compute_day', type="integer", help="Difference in days between creation date and current date",
                                               groups='base.group_user'),
        'date_deadline': fields.date('Deadline'),
        'team_id': fields.many2one('crm.team', 'Sales Team', oldname='section_id',\
                        select=True, help='Sales team to which Case belongs to.\
                             Define Responsible user and Email account for ma.'),
        'partner_id': fields.many2one('res.partner', 'Contact', select=1),
        'company_id': fields.many2one('res.company', 'Company'),
        'description': fields.text('Private Note'),
        'kanban_state': fields.selection([('normal', 'Normal'),('blocked', 'Blocked'),('done', 'Ready for next stage')], 'Kanban State',
                                         track_visibility='onchange',
                                         help="A Issue's kanban state indicates special situations affecting it:\n"
                                              " * Normal is the default situation\n"
                                              " * Blocked indicates something is preventing the progress of this issue\n"
                                              " * Ready for next stage indicates the issue is ready to be pulled to the next stage",