RHV-H 'imgbase check' command fails

Issue

• On our RHV-H hypervisor, the imgbase check command fails:

# imgbase check
Status: FAILED
Bootloader ... OK
  Layer boot entries ... OK
  Valid boot entries ... OK
Mount points ... OK
  Separate /var ... OK
  Discard is used ... OK
Basic storage ... OK
  Initialized VG ... OK
  Initialized Thin Pool ... OK
  Initialized LVs ... OK
Thin storage ... FAILED - It looks like the LVM layout is not correct. The reason could be an incorrect installation.
  Checking available space in thinpool ... FAILED - Data or Metadata usage is above threshold. Check the output of `lvs`
  Checking thinpool auto-extend ... OK

• lvs output shows that thin pool metadata is almost 100%:

# lvs -a
  LV                      VG   Attr       LSize  Pool   Origin                Data%  Meta%  Move Log Cpy%Sync Convert
  [lvol0_pmspare]         rhvh ewi------- 88.00m
  pool00                  rhvh twi-cotzM-  5.44t                              11.86  99.95
  [pool00_tdata]          rhvh Twi-ao----  5.44t
  [pool00_tmeta]          rhvh ewi-ao---- 88.00m
  rhvh-4.0-0.20170104.0   rhvh Vwi---tz-k  5.42t pool00 root
  rhvh-4.0-0.20170104.0+1 rhvh Vwi-aotz--  5.42t pool00 rhvh-4.0-0.20170104.0 11.80
  root                    rhvh Vwi-a-tz--  5.42t pool00                       0.17
  swap                    rhvh -wi-ao----  4.00g
  var                     rhvh Vwi-aotz-- 15.00g pool00                       4.09