My suggestion is that you can try saving the configuration in incognito mode with all roles selected.
But if it still disappears, open a Meraki support ticket. They can check the backend logs and confirm if the configuration is being silently rejected.
You can also test with a different network or create a new test network to see if the issue persists.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
Please, if this post was useful, leave your kudos and mark it as solved.