SSM fingerprint changed

Hey all, hoping someone can help me out here. I'm running SSM on a few instances in a hybrid setup, ie it is installed on actual PCs. All the PCs are Ubuntu. SSM works wonderfully on there. However, today I did an OS upgrade from Ubuntu 18 to 20 and the SSM agent went mental. The main error is this

Jan 25 18:46:16 p0xxxxx amazon-ssm-agent\[3863\]: 2022-01-25 18:46:15 INFO \[OnPremCredsProvider\] Calculated hardware difference, regenerating fingerprint...

Jan 25 18:46:16 p0xxxxxx amazon-ssm-agent\[3863\]: 2022-01-25 18:46:15 ERROR \[CredentialRefresher\] Retrieve credentials produced unrecoverable aws error: MachineFingerprintDoesNotMatch: Fingerprint does not match 9366ec5a-de7a-4aeb-a6db-998a0f1747d7

It is reporting that everything changed, ip, disk, memory, cpu etc etc so it is generating a completely new fingerprint for the box. I have two questions on this

1. Can I somehow change the fingerprint in SSM so that this can connect again, or do I have to do a new activation?
2. How can I prevent this? I know in the AWS docs there is a command you're supposed to be able to run where you umount /etc/machine-id and then do something else. On my boxes the machine-id is not mounted so the command seems to have no effect.