When you eject a USB drive from windows, you expect no more disk activity on that drive.

However, after I eject a USB drive (a hard drive on an external usb docking station), the drive activity light on the usb station would flash for a second, about 10 seconds after windows says it is safe to remove the drive.

This shouldn't be happening but it does, consistently, everytime. How can I debug or narrow down what process is accessing this ejected drive, and what it is accessing (read? write?)

windows 10 pro 64 bit version 10.0.19045