distinction between nkit.rvz and rvz

[clad1984]

I want convert my whole collection of Nintendo Gamecube ROMs from Redump Verified ISOs to RVZs.
However, there is no current updated version DATs for Redumps in RVZ format.
I found this tool, had a test run on the rom ＂Gekkan Nintendo Tentou Demo 2005.10.1 (Japan)"
Two files I got here.

A. Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).iso.rvz <- input :Redump-checked iso , output :rvz by dolphintool
B. Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).nkitrvz.rvz <- DL from somewhere, the filename tells it's in nkit rvz format

I was expecting verifydump tells only A. is GOOD with latest Redump DAT file, but actually it says BOTH files are GOOD.

Loading` Datfile "Nintendo - GameCube - Datfile (1991) (2024-04-22 06-09-43).dat" from "kk.zip"
Datfile loaded successfully with 1991 games
Verifying dump file "C:\Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).iso.rvz"
Verifying dump file "C:\Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).nkitrvz.rvz"
2 dumps had errors:
Dump file "Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).iso.rvz" found in Dat, but it should be named "Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).rvz"
Dump file "Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).nkitrvz.rvz" found in Dat, but it should be named "Gekkan Nintendo Tentou Demo 2005.10.1 (Japan).rvz"

Is there anything I misunderstood or it's just a bug ?