Last week, I discovered that I had an issue with my custom printing service, so I reverted my maps to the ArcGIS default service and stopped the custom print service. I was only using the custom printing service in one web app (or so I thought), but now I'm getting constant warning messages in my Server log file:

My question: is there any way to start with a service and trace the source of the calls to it? I've checked, rechecked, and triple checked every web app that I have and cannot find anything referring to the custom print service.