Did this recently start for you? I don't use onedrive unless I need to so I installed it for this test. I experienced the same as you When you delete a file Photo Mechanic is calling the operating system's routine for moving the file to the trash, so really whatever happens after that is under the control of the OS and not Photo Mechanic.
You'll also see here that one of the Core Developers for Electron (an widely-used application framework) says something similar, and we are actually using the same code as the person that file the bug with Electron:
https://github.com/electron/electron/issues/38541Photo Mechanic does have a setting for whether a file should go to the trash or just be deleted immediately (I've attached a screenshot of the setting). If you disable this, the file no longer goes to the root of the OneDrive folder, it just gets deleted immediately. So, while this does workaround the issue, it's a dangerous setting to enable because you now no longer have the option to recover them from the trash.