Content Delivery API returns incorrect route for unpublished variant document in preview mode

[nhudinh0309]

Which Umbraco version are you using?

16.4.0

Bug summary

When creating a variant content item with two cultures (en-US and da), publishing only the en-US culture while keeping da culture saved but unpublished, the Content Delivery API (called with preview mode) returns an incorrect route value for the da variant.

Specifics

No response

Steps to reproduce

1. Create a variant content item with two cultures: English (en-US) and Danish (da).
2. Publish the en-US culture.
3. Save the da culture without publishing.
4. Call the Content Delivery API with the preview header enabled and Accept-Language is da
5. Check the route value in the API response for the da culture.

Expected result / actual result

Expected result
The API should return the correct route value for the da culture (same as path value in da cultures)

Actual result
The API returns an incorrect route value for the da culture

[AndyButland]

Fixed via #20499 for 16.4 and 17.0.