The license stays with the Meraki Organization. You lose licese if you ove the device to a different organization and not move the licese with it.
Moving to different organisation or network is where you will lose the config. If you are not moving them then no issues.
If the MSP has set it up that the customer network in in a shared organisation. Then thats where the customer will have licese and config issues. When the device is migrated into a new organization.