If you’re taking the picture immediately before you set the options, insert a 500ms delay between the setOptions (brackets) and the camera.takePicture. This might help.
Another potential issue is the floating point numbers like 2.1.
See this discussion.
If you read the thread, you can see the ultimate solution was to insert a delay. However, keep in mind that at the time of the discussion, the bracket option was new and the developer was originally taking individual pictures.
If there is any error in the debug console, that would be useful.