Hi,
No, Meraki doesn't intentionally slow down the speed during the grace period. The grace period typically refers to the time when a device is being registered or when a firmware update is in progress. During this time, network performance may be temporarily affected due to the device not being fully functional yet or the update process consuming resources, but there's no throttling or intentional slowdown by Meraki.
If you're noticing a significant drop in speed during this period, it might be worth checking for other factors, like network congestion, bandwidth usage, or device configuration issues.