Azure Functions SQL output binding JSON problem

I am experiencing a problem with JSON columns in my Azure Function. For some reason, my MS SQL server throws an error due to unsupported syntax in the UPSERT command. The command contains `JSON(MAX)` which seems to be unsupported syntax. I indeed think this is not valid syntax (https://learn.microsoft.com/en-us/sql/t-sql/data-types/json-data-type?view=azuresqldb-mi-current).

It feels weird that I wasn't able to find any report on this problem, so I may be just doing something wrong. Sorry for wasting your time if this is my mistake guys.

**Azure Functions Core Tools**
```
Core Tools Version: 4.8.0+ec58eb7110992ea02aa19e9c060e45ac8882cc02 (64-bit)
Function Runtime Version: 4.1046.100.25610
```

**host.json**
```json
{
"version": "2.0",
"logging": {
"logLevel": {
"default": "Warning",
"Function": "Debug"
},
"applicationInsights": {
"samplingSettings": {
"isEnabled": true,
"excludedTypes": "Request"
}
}
},
"extensionBundle": {
"id": "Microsoft.Azure.Functions.ExtensionBundle",
"version": "[4.32, 5.0.0)"
}
}
```

**Database schema**
```sql
IF OBJECT_ID('Reviews_Process_v2', 'U') IS NULL
BEGIN
CREATE TABLE Reviews_Process_v2 (
id varchar(150) PRIMARY KEY,
status nvarchar(50),
batch_id varchar(100),
positive_aspects nvarchar(max),
negative_aspects nvarchar(max),
user_language nvarchar(50),
suggested_answer_cz nvarchar(max),
suggested_answer_en nvarchar(max),
request JSON,
response JSON
);

-- Index on status
CREATE NONCLUSTERED INDEX IX_Reviews_Process_v2_Status
ON Reviews_Process_v2 (status);

-- Index on batch_id
CREATE NONCLUSTERED INDEX IX_Reviews_Process_v2_BatchId
ON Reviews_Process_v2 (batch_id);
END
```

**Error text**
```
[2026-03-31T15:57:17.816Z] Exception executing query. Message=Column, parameter, or variable Azure/azure-functions-extension-bundles#9: Cannot specify a column width on data type json.
[2026-03-31T15:57:17.817Z] Column, parameter, or variable Azure/azure-functions-extension-bundles#10: Cannot specify a column width on data type json.
[2026-03-31T15:57:17.817Z] Parameter or variable 'json' has an invalid data type.
[2026-03-31T15:57:17.817Z] Parameter or variable 'json' has an invalid data type.
[2026-03-31T15:57:17.817Z] Query=WITH cte AS ( SELECT * FROM OPENJSON(REPLACE(@rowData, N'/', N'\/')) WITH ([id] varchar(150),[source] varchar(50),[status] nvarchar(50),[batch_id] varchar(100),[positive_aspects] nvarchar(max),[negative_aspects] nvarchar(max),[user_language] nvarchar(50),[suggested_answer_cz] nvarchar(max),[suggested_answer_en] nvarchar(max),[request] json(max),[response] json(max)) )
[2026-03-31T15:57:17.817Z] MERGE INTO [dbo].[Reviews_Process_v2] WITH (HOLDLOCK)
[2026-03-31T15:57:17.817Z] AS ExistingData
[2026-03-31T15:57:17.817Z] USING cte
[2026-03-31T15:57:17.817Z] AS NewData
[2026-03-31T15:57:17.817Z] ON
[2026-03-31T15:57:17.817Z] ExistingData.[id] = NewData.[id]
[2026-03-31T15:57:17.817Z] WHEN MATCHED THEN
[2026-03-31T15:57:17.817Z] UPDATE SET ExistingData.[id] = NewData.[id], ExistingData.[source] = NewData.[source], ExistingData.[status] = NewData.[status], ExistingData.[batch_id] = NewData.[batch_id], ExistingData.[positive_aspects] = NewData.[positive_aspects], ExistingData.[negative_aspects] = NewData.[negative_aspects], ExistingData.[user_language] = NewData.[user_language], ExistingData.[suggested_answer_cz] = NewData.[suggested_answer_cz], ExistingData.[suggested_answer_en] = NewData.[suggested_answer_en], ExistingData.[request] = NewData.[request], ExistingData.[response] = NewData.[response]
[2026-03-31T15:57:17.817Z] WHEN NOT MATCHED THEN
[2026-03-31T15:57:17.817Z] INSERT ([id],[source],[status],[batch_id],[positive_aspects],[negative_aspects],[user_language],[suggested_answer_cz],[suggested_answer_en],[request],[response]) VALUES ([id],[source],[status],[batch_id],[positive_aspects],[negative_aspects],[user_language],[suggested_answer_cz],[suggested_answer_en],[request],[response]);
[2026-03-31T15:57:17.911Z] Executed 'Functions.enqueue_reviews_batch_http' (Failed, Id=5162ac02-6da9-484c-986e-fc5f29c6787a, Duration=10367ms)
[2026-03-31T15:57:17.912Z] System.Private.CoreLib: Exception while executing function: Functions.enqueue_reviews_batch_http. Microsoft.Azure.WebJobs.Host: Error while handling parameter _binder after function returned:. Microsoft.Azure.WebJobs.Extensions.Sql: Unexpected error upserting rows. Core Microsoft SqlClient Data Provider: Column, parameter, or variable Azure/azure-functions-extension-bundles#9: Cannot specify a column width on data type json.
[2026-03-31T15:57:17.912Z] Column, parameter, or variable Azure/azure-functions-extension-bundles#10: Cannot specify a column width on data type json.
[2026-03-31T15:57:17.912Z] Parameter or variable 'json' has an invalid data type.
[2026-03-31T15:57:17.912Z] Parameter or variable 'json' has an invalid data type.
```

**Azure Function definition**
```python

SQL_CONNECTION_STRING = "SqlConnectionString"
ENQUEUE_SQL_INPUT_ARGNAME = "inputDocuments"
# Larger batches are not well supported because the connection to the SQL database becomes
# unstable when transferring large amounts of data. Not sure what's the root cause but limiting
# to 500 reviews per batch seems to work reliably.
ENQUEUE_SQL_INPUT_COMMAND = """
SELECT TOP (20)
input.ReviewID AS id,
input.ReviewSource as source,
output.status,
input.Author as author,
input.ReviewerComment as comment,
output.positive_aspects,
output.negative_aspects,
output.user_language,
output.suggested_answer_cz,
output.suggested_answer_en,
output.batch_id,
output.request,
output.response
FROM [AI_Reviews].[dbo].[OverALL] input
LEFT JOIN [AI_Reviews].[dbo].[Reviews_Process_v2] output
ON input.ReviewID = output.id
WHERE (output.status IS NULL OR output.status = 'to_retry')
ORDER BY input.ReviewDate DESC;
"""
ENQUEUE_SQL_INPUT_TYPE = "Text"
ENQUEUE_SQL_OUTPUT_BATCHES_ARGNAME = "llmBatches"
# Note that the command is the name of the table. Specifying the database will not have any effect.
# Instead, the connection string must specify the database to connect to. If the table is not in the
# configured database, the function will fail to write to the table.
ENQUEUE_SQL_OUTPUT_BATCHES_COMMAND = "[dbo].[Batches_v2]"
ENQUEUE_SQL_OUTPUT_REVIEWS_ARGNAME = "reviewsEnqueued"
ENQUEUE_SQL_OUTPUT_REVIEWS_COMMAND = "[dbo].[Reviews_Process_v2]"

@app.function_name(name="enqueue_reviews_batch_timer")
@app.timer_trigger(arg_name="timer", schedule="0 0 * * * *", use_monitor=True)
@app.sql_input(
arg_name=ENQUEUE_SQL_INPUT_ARGNAME,
command_text=ENQUEUE_SQL_INPUT_COMMAND,
command_type=ENQUEUE_SQL_INPUT_TYPE,
connection_string_setting=SQL_CONNECTION_STRING,
)
@app.sql_output(
arg_name=ENQUEUE_SQL_OUTPUT_BATCHES_ARGNAME,
command_text=ENQUEUE_SQL_OUTPUT_BATCHES_COMMAND,
connection_string_setting=SQL_CONNECTION_STRING,
)
@app.sql_output(
arg_name=ENQUEUE_SQL_OUTPUT_REVIEWS_ARGNAME,
command_text=ENQUEUE_SQL_OUTPUT_REVIEWS_COMMAND,
connection_string_setting=SQL_CONNECTION_STRING,
)
def enqueue_reviews_batch_timer_func(
timer: func.TimerRequest,
llmBatches: func.Out[func.SqlRow],
inputDocuments: func.SqlRowList,
reviewsEnqueued: func.Out[func.SqlRow],
) -> None:
enqueue_reviews_batch(llmBatches, inputDocuments, reviewsEnqueued)
```