I ran into something similar, though a bit different, a few years ago. The text below is from my correspondence with our VAR. Perhaps it might help. 

According to Laserfiche Development, the issue of the ghost instances appearing right after the Laserfiche Forms Routing Service has being restarted might be due to a "recovery submission" . If a submissions could not be processed by the Forms Routing services (why? possibly the forms routing service was either down or not responding at the time the submission was submitted), those submissions get stored under C:\ProgramData\Laserfiche Forms\RoutingError. You can check in windows explorer under that path , make sure option "hidden files and folders" is unchecked from Windows to be able to view this folder. When the Forms Routing service gets restarted it will process those submissions again.

To ensure the ghost instances do not appear again when the Routing service gets restarted , please backup the "Routing Error”  folder, then delete it , then restart the service and there should be no more ghost instances.