Just in case you are not following the Service notices:
"If you are seeing urgent impact on your networks, please proceed to temporarily modify the RF Profile to have the Minimum Bitrate set Per SSID instead of Per band as a workaround, until the issue is fully resolved."
https://community.meraki.com/t5/Meraki-Service-Notices/Failure-of-configuration-fetch-for-MR/bc-p/21...
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