• Package Name: azure-cosmos
• Package Version: 4.9.0
• Operating System: Windows 10
• Python Version: 3.11.3

Describe the bug
When executing a cross-partition query with an ORDER BY clause, the initial request for the first page of results succeeds and returns a continuation token. However, when a subsequent request is made with the exact same query and the provided token to fetch the next page, the Cosmos DB service returns an HTTP 400 Bad Request with an "Invalid Continuation Token" error. This makes paginated, sorted queries across multiple partitions unusable.

To Reproduce
Steps to reproduce the behavior:

1. Create a Cosmos DB container with a partition key (e.g., /user_id).
2. Using the Python SDK, execute a cross-partition query that includes an ORDER BY clause but does not filter on the partition key.
   • Example Query: SELECT * FROM c WHERE c.conversationStartTime >= @start AND c.conversationStartTime <= @end ORDER BY c.conversationStartTime DESC
3. The first request (with continuation_token=None) succeeds and returns a page of items and an opaque, non-JSON continuation token string.
4. Execute the exact same query again for the second page, providing the continuation token from the previous step.

Expected behavior
The second request should succeed and return the next page of sorted results, along with a new continuation token (or None if it's the last page).

Screenshots
If applicable, add screenshots to help explain your problem.

error_order_by_logs.txt

Additional context
This issue has been thoroughly debugged, and the following has been confirmed:

1. Environment Stack:

   • Azure Functions Core Tools: 4.0.6280
   • Azure Functions Runtime: 4.834.3.22875

2. Token Integrity: Through extensive logging down to the raw HTTP request, we have confirmed that the full, unmodified continuation token string is being correctly placed in the x-ms-continuation header. The token is not being truncated or corrupted by the client application, the SDK, or any networking components.

3. Token Format Analysis: We have verified that a query without the ORDER BY clause works perfectly with pagination. This working query uses a structured JSON continuation token. The failing ORDER BY query uses a different, opaque string token format. Our application handles both formats correctly by Base64-encoding them, proving the client-side logic is sound.

4. Critical Workaround Discovery: A successful workaround was found. If the query is modified to be a single-partition query by adding a WHERE clause that filters on the partition key (e.g., ... AND c.user_id = @user_id), the pagination with ORDER BY works perfectly.

This analysis isolates the bug specifically to the server-side processing of continuation tokens for cross-partition ORDER BY queries.