Steps to reproduce: - Let's consider the portal user Pu, the project Pr and the task Ta - Add Pu as a follower of Pr - Log as Pu and open Ta - Try to post a message Bug: An access error was raised due to the rule "res_partner: portal/public: read access on my commercial partner". opw:2070320 closes odoo/odoo#36960 Signed-off-by: Simon Goffin (sig) <sig@openerp.com>