Renamed external drive still appearing in terminal with both old and new names I have an external drive connected to my MacBook Air via USB 3.1 Gen 2 through a TB3 hub.
A few weeks ago I changed name of the drive from Mercury 1TB to just Mercury.  This was done in the Finder.
I find that when I in Terminal ls /Volumes I unexpectedly see both the the old name and the new name listed.
I can cd into the old volume but when I try to ls I get Permission denied.
In Disk Utility I can only see the new volume (Mercury).  First Aid function finds no problems to repair.
I have restarted many times but have not taken any other troubleshooting actions.
I also occasionally have KPs when the machine is idle, but this is likely unrelated as they started before the renaming.
Why is this old name still appearing and what can be done about it?
See screenshot from terminal:

Update to add:
The mystery volume does not appear on the desktop.  It appears in the /Volumes directory even when the external drive is powered off.
When I sudo ls -al the only file that is present is .Spotlight-V100.
Here's there result of diskutil list as requested in comments:
diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     314.6 MB   disk0s1
   2:                 Apple_APFS Container disk1         500.0 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +500.0 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume Macintosh HD            11.3 GB    disk1s1
   2:                APFS Volume Macintosh HD - Data     167.3 GB   disk1s2
   3:                APFS Volume Preboot                 82.0 MB    disk1s3
   4:                APFS Volume Recovery                528.9 MB   disk1s4
   5:                APFS Volume VM                      5.4 GB     disk1s5

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                 Apple_APFS Container disk3         1000.0 GB  disk2s2

/dev/disk3 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1000.0 GB  disk3
                                 Physical Store disk2s2
   1:                APFS Volume Mercury                 11.0 GB    disk3s1
My first guess with the elements you give is that something went wrong while renaming. The old drive you see in Volume is the old mounting point of your drive and it still contains the index file for spotlight.
I would just delete this folder using:
sudo rm -rf '/Volumes/Mercury 1TB'/.Spotlight-V100
sudo rmdir '/Volumes/Mercury 1TB'

*Updated after nohillside's comment in the thread down below.