This is a bit of an oversimplification of our product but Ivanti Patch for SCCM is simply an add-on to SCCM that allows you to publish 3rd party updates. We get these updates directly from the vendor sites with URL's they provide, we then publish those updates for deployment. After publishing and syncing to the WSUS our software is no longer involved in the processes moving forward. SCCM will package and deploy the software, and the OS will install the update similarly to if you would execute it manually.
Most likely the file is being generated by either the update itself or part of the packaging SCCM does. However, I am unable to replicate the issue you are seeing in my testing environment and I was unable to find any past cases of this particular issue. Its also possible it's a temp file that is simply not deleted after the installation. As mentioned, this is happening far outside the parameters of our software, but I hope the information provided is helpful and leads you to solution.