Revision on https://github.com/odoo/odoo/commit/5f8d3c61bee40d027efc5041cdc4bca5e67c42d7 Before this commit, there was a traceback when you had two needaction notifications related to the same document. This is caused by a typo in the commit above: the object `similarItem` has a property `messageIDs`, but the code wrongly access the property `messagesIDs` (see the extra "s"). Steps to reproduce: - Set notification management to 'Handle with Odoo' for Admin - Demo mention Admin twice on a specific project task - Admin opens messaging menu Display error `Cannot read property 'concat' of undefined` Issue reported on this PR comment: https://github.com/odoo/odoo/pull/28462#pullrequestreview-175001349 Task-ID 1909521 closes odoo/odoo#28703