Our technicians have been going through workstations and removing Dropbox. But this change does not appear in inventory. When looking at detailed inventory of some machines the next day, it still shows Dropbox under installed software.

We have gone through following steps on several workstations:
1. Uninstall Dropbox.
2. Force inventory scan on workstation.
3. View detailed inventory of this workstation in ZCC. Dropbox is not shown as installed. Also, Dropbox is not shown if viewing inventory details directly on the workstation.
4. Next day - view detailed inventory of this workstation in ZCC. Dropbox is again shown as being installed.
5. Verify on the workstation that Dropbox is actually not present in Add/Remove programs, nor does it exist in the directory that is shown in detailed inventory.
6. Look at inventory details directly on the workstation - Dropbox is shown as installed (in the directory where it doesn't actually exist).

I've looked through loader-messages.log on the server, as well as services-messages.log and colw32.log on the workstation, but didn't notice anything suspicious.

Both server and workstations are running version 11.3.

What on earth is going on?