[Python] RestException: INVALID_PARAMETER_VALUE while searching for registered models from...

The Code:

client = MlflowClient()
registered_models = client.search_registered_models()
print(registered_models)


The error is happening in line 2:

RestException: INVALID_PARAMETER_VALUE: Response:
{'Error': {'Code': 'UserError', 'Severity': None,
'Message': "Currently unsupported filter string format (we currently do not support OR).
Provided filter string: tag.`mlflow.prompt.is_prompt` != 'true'",
'MessageFormat': None, 'MessageParameters': None, 'ReferenceCode': None,
'DetailsUri': None, 'Target': None, 'Details': [], 'InnerError': None,
'DebugInfo': None, 'AdditionalInfo': None}, 'Correlation': {'operation':
'48be02fc323be8de54f093e51f494ec7', 'request': '40d8a61e148ab946'},
'Environment': 'eastus', 'Location': 'eastus', 'Time': '2025-05-
20T11:22:55.0282645+00:00', 'ComponentName': 'mlflow', 'statusCode': 400,
'error_code': 'INVALID_PARAMETER_VALUE'}


The code is running on a notebook in AzureML.

The same code was working a couple of weeks ago. It is unclear why this error is coming up now.

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