"Not the same number of function calls and responses" when using Mistral API

[AndreaDiTrani]

• This is actually a bug report.
• I am not getting good LLM Results
• I have tried asking for help in the community on discord or discussions and have not received a response.
• I have tried searching the documentation and have not found an answer.

What Model are you using?

• gpt-3.5-turbo
• gpt-4-turbo
• gpt-4
• Other (please specify) Mixtral 8x22B

Describe the bug
I have some documents regarding electrical components and i am trying to extract the relevant features from them. On some samples of those documents everything works fine but on some of them it fails with the following exception:

MistralAPIException: Status: 400. Message: {"object":"error","message":"Not the same number of function calls and responses","type":"invalid_request_error","param":null,"code":null}

To Reproduce
The pydantic structure i am using is the following:

FieldNames = enum.Enum('FieldNames', {item: item for item in field_list})

class Feature(BaseModel):
    id:int = Field(default = 0, description="Unique ID of the feature")
    feature_tag:FieldNames = Field(default = FieldNames('Power dissipation'), # type: ignore
                                   description = "Simple tag describing the feature") 
    feature_val:str = Field(default = 'none', description="Value of the feature")

class ProductFeatures(BaseModel):
    product:str = Field(default = 'none', description='id of the product')
    features: List[Feature] = Field(default = [Feature()], description="List of features")

and this is the function i'm calling to extract the features

def feature_extractor(info) -> ProductFeatures:
    EXTRACTION_MODEL = "open-mixtral-8x22b"
    messages = [
        {
            "role": "system",
            "content": extraction_prompt,
        },
        {
            "role": "user",
            "content": f"Consider: {info}\n Extract the features.",
        },
    ]
    plan = (
        patched_chat.chat.completions.create(
            model=EXTRACTION_MODEL,
            response_model=ProductFeatures,
            messages=messages,
            temperature=0,
            max_tokens=4096,
        )
    )
    return plan

Expected behavior
The expected behavior is something similar to what happens with "sane" text samples:

{'product': 'X1-IS-AI-02',
 'features': [{'id': 1,
   'feature_tag': <FieldNames.Power dissipation: 'Power dissipation'>,
   'feature_val': '0.65 W (passive Tx), 1.05 W (active Tx) @ 24 Vdc with 20 mA, 24 Vdc + 250 Ω output, typical'},
  {'id': 2,
   'feature_tag': <FieldNames.System Supply: 'System Supply'>,
   'feature_val': '24 Vdc nom (18 to 30 Vdc)'},
  {'id': 3,
   'feature_tag': <FieldNames.Current consumption: 'Current consumption'>,
   'feature_val': '23 mA @ 24 Vdc with 20 mA, typical'},
  {'id': 4,
   'feature_tag': <FieldNames.System Out: 'System Out'>,
   'feature_val': 'Current 4 to 20 mA. The module always sinks current and the Termination Board extends its use to source loops'},
  {'id': 5,
   'feature_tag': <FieldNames.Response time: 'Response time'>,
   'feature_val': '≤ 20 ms (4 to 20 mA or 20 to 4 mA)'},
  {'id': 6,
   'feature_tag': <FieldNames.Current limitation: 'Current limitation'>,
   'feature_val': '25.5 mA typical'},
  {'id': 7,
   'feature_tag': <FieldNames.Maximum load: 'Maximum load'>,
   'feature_val': '600 Ω'},
  {'id': 8,
   'feature_tag': <FieldNames.Maximum voltage: 'Maximum voltage'>,
   'feature_val': '30 V'},
  {'id': 9,
   'feature_tag': <FieldNames.Minimum voltage: 'Minimum voltage'>,
   'feature_val': '15 V (including series resistance voltage drop)'},
  {'id': 10,
   'feature_tag': <FieldNames.Field In: 'Field In'>,
   'feature_val': 'Current 4 to 20 mA, passive or active Tx. Passive Tx line voltage: 15 V minimum @ 20 mA. Active Tx voltage drop: 6.5 V maximum @ 20 mA'},
  {'id': 11,
   'feature_tag': <FieldNames.Fault: 'Fault'>,
   'feature_val': 'An out-of-range fault with configurable limits is available on the common fault line'},
  {'id': 12,
   'feature_tag': <FieldNames.Performance: 'Performance'>,
   'feature_val': 'Ref. Conditions: 24 V supply, 24 V + 250 Ω output, 23 ± 1 °C ambient temperature. Linearity accuracy: ≤ ± 20 µA. Calibration accuracy: ≤ ± 20 µA. Temp. influence: ≤ ± 2 µA/°C. Isolation: Field In/System Out 2.5 kV; Field In/System Supply 2.5 kV; System Out/System Supply 500 V'},
  {'id': 13,
   'feature_tag': <FieldNames.Environmental conditions: 'Environmental conditions'>,
   'feature_val': 'Operating temperature: temperature limits –40 to +70 °C. Storage temperature: temperature limits –45 to +80 °C'},
  {'id': 14,
   'feature_tag': <FieldNames.Safety description: 'Safety description'>,
   'feature_val': 'Associated apparatus and non-sparking electrical equipment'},
  {'id': 15,
   'feature_tag': <FieldNames.Mounting: 'Mounting'>,
   'feature_val': 'On custom Termination Board'},
  {'id': 16,
   'feature_tag': <FieldNames.Weight: 'Weight'>,
   'feature_val': 'about 55 g'},
  {'id': 17,
   'feature_tag': <FieldNames.Dimensions: 'Dimensions'>,
   'feature_val': 'Width 10 mm, Depth 80 mm, Height 120 mm'}]}

If needed i can provide the prompts i'm using and also the text i'm trying to extract

Screenshots
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