Invalid Handle to Path

Apologies for not having given enough script details. The message that you reported was:

The script returned exit code 255, but 0 was expected: Exit code: 255
Error: unable to determine volume group (VG) for /home/myuser

so it seemed like it might be:

if [ -z "$LVMID" ]
then
        EXIT_CODE=-1
        echo "Error: unable to determine volume group (VG) for $NAME"
        exit $EXIT_CODE
fi

-1 would be 255 as an unsigned 8-bit value. $NAME is /home/myuser, and goes after the name of the script:

#!/bin/bash

# This script returns the device on which the volume is mounted
# 
# Input is always:
#  $1 = name of the folder to locate the LVM device for

That will probably avoid the complaints from df (which expected $NAME).

For the file permissions, root should be able to get by that, but a locked file might still error. You could test it.
It’s disappointing that it’s not an empty file just used to lock. This claims it can be removed after a Skype exit. Perhaps it’s normally supposed to be removed? Or is it always there? In GitHub steps, you said Skype open.

Does a Skype exit let you see the file, or does it go away? If still there, you can examine it to guess what it is.
Filtering would be the workaround. Ideally we (and it might need someone else too) can figure this out some.