Didn't heard anything about studio one being linked to one drive etc ... I think the issue comes from your one drive settings, you may have something like auto cloud sync activated or something which would mean that the new files you downloaded where just backed up to your one drive cloud.
If you don't wan't such a thing, i would recommend :
- access to your one drive delete what you need and check up the settings to disable auto syncs etc
- open task manager on windows, reach the "starting" tab and disable the launch on start for one drive
you shouldn't be annoyed anymore after this,
Hope this might help,