In some cases, objects may go missing in the normalized PDF generated by the "Normalize PostScript / PDF / Illustrator 8.0 File" task when Converting Spot colors to a Destination Color Space.
Symptoms
Objects that are in the input Adobe® PDF go missing in the Normalized PDF output.
Running this same task (Normalize PostScript / PDF / Illustrator 8.0 File) on Automation Engine 12.0.0 or 12.1.1 produces correct result.
For long term solution, upgrade Automation Engine to version 12.1.1.
Workaround
Normalize PDF task may be used as a work around. But it needs to be followed by Optimize PDF Separations task to convert colors. Some customers may not have the PDF Processor module to do so.