Auto-propagation settings can be configured by the project manager. In this case, the settings of the people you assign to this project don’t have any effect, nor can assignees change these settings.
You can set up auto-propagation and confirmation of auto-propagated text for the current project. To do that, click the Repetitions button on the project’s page.
Note that if you don’t specify settings for each project, the personal settings of each assignee will apply to the project.