I am trying to update a multi-value lookup field via the REST Api in a workflow. It works great in Fiddler. However, when I run the workflow I get a 400 bad request error. When I log everything in the Workflow, it looks correct.
My URL: https://sites.generic/sites/PSA/projecttracker/_api/Web/Lists/getbytitle('Doc%20Central')/items(42)
Accept: application/json;odata=verbose Content-Type: application/json;odata=verbose
The content lines I have logged straight from the workflow. Visually it looks correct. I am guessing that SP is adding something to break it.