100% CPU utilization doesn't make queries fail directly. It makes them run slower. If there is a timeout set on the client, then the slowness may cause the timeout to be hit, which fails the query.
For details on the two CPU metrics, see https://learn.microsoft.com/en-us/azure/azure-sql/database/resource-limits-logical-server?view=azuresql#resource-consumption-by-user-workloads-and-internal-processes
Regards,
Oury