how to handle severity of 'Unknown'?

[simonsdave]

Starting to see severities of 'Unknown'. How should this be handled?

2020-11-27 12:13:59 ERROR io:126 Could not read vulnerabilities from '/tmp/tmp.kFFNaM/ff72598b05f57e6f83d56b858ba9783796e99aea2dcef391b3fa688c1e077ae5.json' - 'Unknown' is not one of ['negligible', 'Negligible', 'low', 'Low', 'medium', 'Medium', 'high', 'High']

Failed validating 'enum' in schema['properties']['Severity']:
    {'enum': ['negligible',
              'Negligible',
              'low',
              'Low',
              'medium',
              'Medium',
              'high',
              'High'],
     'type': 'string'}

On instance['Severity']:
    'Unknown'