/usr/lib/udev/rules.d/55-scsi-sg3_id.rules contains the statement:

-->
# If the 'inquiry' sysfs attribute is present the kernel will already
# have scanned for VPD pages, so if the vpd page attribute is not
# present it is not supported (or deemed unsafe to access).
# Hence we can skip the call to sg_inq and avoid I/O altogether.
--<

On my Leap 42.2 I have attached an usb stick that has:

-->
# ll /sys/block/sdd/device/inquiry
-r--r--r-- 1 root root 0 Jul 25 13:06 /sys/block/sdd/device/inquiry
--<

but no vpd pages attributes:

-->
 # ll /sys/block/sdd/device/vpd*
ls: cannot access '/sys/block/sdd/device/vpd*': No such file or directory
--<

Still, the vpd enquriy is executed and the stick seems to be misidentified as
harddisk:

-->
# udevadm test /block/sdd
[...]
IMPORT '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/inquiry --raw'
/usr/lib/udev/rules.d/55-scsi-sg3_id.rules:14
starting '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/inquiry --raw'
'/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/inquiry --raw'(out)
'SCSI_IDENT_SERIAL=u'
Process '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/inquiry --raw'
succeeded.
IMPORT '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg80 --raw'
/usr/lib/udev/rules.d/55-scsi-sg3_id.rules:24
starting '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg80
--raw'
'/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg80 --raw'(err)
'unable to open binary file /sys/block/sdd/device/vpd_pg80: No such file or
directory'
Process '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg80 --raw'
failed with exit code 15.
IMPORT '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg83 --raw'
/usr/lib/udev/rules.d/55-scsi-sg3_id.rules:27
starting '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg83
--raw'
'/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg83 --raw'(err)
'unable to open binary file /sys/block/sdd/device/vpd_pg83: No such file or
directory'
Process '/usr/bin/sg_inq --export --inhex=/sys/block/sdd/device/vpd_pg83 --raw'
failed with exit code 15.
-->

Same misidentification in the multipath rules:

-->
PROGRAM '/sbin/multipath -u -i sdd' /usr/lib/udev/rules.d/56-multipath.rules:25
starting '/sbin/multipath -u -i sdd'
Process '/sbin/multipath -u -i sdd' failed with exit code 1.
LINK 'disk/by-id/scsi-S__u' /usr/lib/udev/rules.d/58-scsi-sg3_symlink.rules:12
LINK 'disk/by-id/scsi-S__u'
/usr/lib/udev/rules.d/60-persistent-storage.rules:48
--<

That breaks the udisks2 functionality.