The full mail composer now shows “Log” instead of “Send” when the action is meant to record a message rather than send one. This makes the button label better match the user’s intended action and reduces confusion.

Task : https://www.odoo.com/web#id=33471&view_type=form&model=project.task&action=327&menu_id=4720
Pad : https://pad.odoo.com/p/r.278e95582cd6483964168e2b6783bf2e