Description of problem:

B. index_memory_size_mb is required to set but index_memory_size to see it w/ lvs

[root@hayes-01 ~]# lvconvert --yes --type vdo-pool -n vdo_lv --vdosettings 'vdo_index_memory_size=256' -V 20G vdo_sanity/vdo_pool
Unknown VDO setting "vdo_index_memory_size".

[root@hayes-01 ~]# lvconvert --yes --type vdo-pool -n vdo_lv --vdosettings 'vdo_index_memory_size_mb=256' -V 20G vdo_sanity/vdo_pool
WARNING: Converting logical volume vdo_sanity/vdo_pool to VDO pool volume with formating.
THIS WILL DESTROY CONTENT OF LOGICAL VOLUME (filesystem etc.)
The VDO volume can address 2 GB in 1 data slab.
It can grow to address at most 16 TB of physical storage in 8192 slabs.
If a larger maximum size might be needed, use bigger slabs.
Logical volume "vdo_lv" created.
Converted vdo_sanity/vdo_pool to VDO pool volume and created virtual vdo_sanity/vdo_lv VDO volume.

[root@hayes-01 ~]# lvs -o vdo_index_memory_size_mb vdo_sanity/vdo_lv
[...]
Unrecognised field: vdo_index_memory_size_mb

[root@hayes-01 ~]# lvs -o vdo_index_memory_size vdo_sanity/vdo_lv
VDOIndexMemorySize
256.00m

C. same with block_map_cache_size_mb

[root@hayes-01 ~]# lvs -o vdo_block_map_cache_size_mb vdo_sanity/vdo_lv
[...]
Unrecognised field: vdo_block_map_cache_size_mb

[root@hayes-01 ~]# lvs -o vdo_block_map_cache_size vdo_sanity/vdo_lv
VDOBlockMapCacheSize
128.00m

[root@hayes-01 ~]# lvchange --vdosettings 'vdo_block_map_cache_size = 256' vdo_sanity/vdo_pool
Unknown VDO setting "vdo_block_map_cache_size".
[root@hayes-01 ~]# lvchange --vdosettings 'vdo_block_map_cache_size_mb = 256' vdo_sanity/vdo_pool
Logical volume vdo_sanity/vdo_pool changed.

[root@hayes-01 ~]# lvs -o vdo_block_map_cache_size vdo_sanity/vdo_lv
VDOBlockMapCacheSize
256.00m

Version-Release number of selected component (if applicable):
kernel-4.18.0-398.g366e.el8.kpq1 BUILT: Tue Jun 7 04:56:38 CDT 2022
lvm2-2.03.14-4.el8 BUILT: Wed Jun 15 17:14:34 CDT 2022
lvm2-libs-2.03.14-4.el8 BUILT: Wed Jun 15 17:14:34 CDT 2022

How reproducible:
Everytime