Site Health monitoring is still being reported in the MainWP Dashboard despite being disabled in the global settings.
It appears that the per site settings do not inherit the on/off value from the global setting.
My experience with the WordPress Site Health feature has been contentious at best due to it regularly lodging warnings that clear on their own when visiting the site’s Site Health page. Since it does nothing but generate noise, I’d just as soon leave it disabled globally. While it might clear the unwanted reporting, I’d prefer not to have to individually disable the Site Health monitoring on my child sites.
I have submitted a ticket with screenshots of the relevant settings.