Found proof with NFT plot but got "Invalid proof of space" on seemingly good plot and farmer (Flax) (SOLVED)

I know this is Chia forum and my issue is on Flax but I think it could happen on Chia as well since they share almost entire code (before Pool protocol).
I’m afraid it could happen again since I can’t find anything wrong and it could happen on Chia so I want to catch it before it is too late.
Maybe it is a bug or I’m missing something important.

In my logs I found out that I found a proof and I did not win a block so I investigated and did not came up with concise explanation.
I dug up the exact plot based on “Plot Key”.
I checked that plot against 50 challenges in Chia and 30 challenges in flax and it seems to be fine.
Response time of my farmer was 1.221 s.
Keys are all ok since I’m finding proofs for Chia pool regularly and I found several proofs and won block on Flax as well.

Do somebody have explanation on this behavior?

PLOT:
plot-k32-2021-08-03-06-26-33889xxxxxxxxxxxx

LOG EXTRACT:
2021-08-04T15:31:09.864 harvester flax.harvester.harvester: INFO     4 plots were eligible for farming 5xxxxx62ca... Found 1 proofs. Time: 1.22131 s. Total 1035 plots
2021-08-04T15:31:09.895 farmer flax.farmer.farmer         : ERROR    Invalid proof of space {'challenge': '0x1a3a41205485c4a75db1d2fc069052c5f3f6ed9d7a643e51a9769fc6beb61b51',
 'plot_public_key': '0x8e418f7fb8b90bf5882e2a08e7xxxxxxxxxxxxxxxxxxxxxxxxxxea272ad15b212dad836b0',
 'pool_contract_puzzle_hash': '0xdaec63d99ad46fe6312d0xxxxxxxxxxxxxxxxxxxxxxb5270df00d52',
 'pool_public_key': None,
 'proof': '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',
 'size': 32}
2021-08-04T15:31:15.845 full_node flax.full_node.full_node: INFO       Finished signage point 3/64: CC: 6e2249ede96d86a5143ec7e7552c45213a5f13d6d801e5b3e0b0063dd986f5c2 RC:
FLAX CHECK:
2021-08-07T10:06:11.751  flax.plotting.check_plots        : INFO     Testing plot X:\plot-k32-2021-08-03-06-26-33889df57xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.plot k=32
2021-08-07T10:06:11.752  flax.plotting.check_plots        : INFO        Pool public key: None
2021-08-07T10:06:11.764  flax.plotting.check_plots        : INFO        Farmer public key: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
2021-08-07T10:06:11.766  flax.plotting.check_plots        : INFO        Local sk: <PrivateKey xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
2021-08-07T10:07:42.356  flax.plotting.check_plots        : INFO        Proofs 30 / 30, 1.0
2021-08-07T10:07:42.358  flax.plotting.check_plots        : INFO
2021-08-07T10:07:42.359  flax.plotting.check_plots        : INFO
2021-08-07T10:07:42.359  flax.plotting.check_plots        : INFO     Summary
2021-08-07T10:07:42.359  flax.plotting.check_plots        : INFO     Found 1 valid plots, total size 0.09896 TiB
2021-08-07T10:07:42.361  flax.plotting.check_plots        : INFO     1 plots of size 32
CHIA CHECK:
2021-08-07T10:04:54.507  chia.plotting.check_plots        : INFO        Proofs 48 / 50, 0.96
2021-08-07T10:04:54.509  chia.plotting.check_plots        : INFO
2021-08-07T10:04:54.510  chia.plotting.check_plots        : INFO
2021-08-07T10:04:54.511  chia.plotting.check_plots        : INFO     Summary
2021-08-07T10:04:54.511  chia.plotting.check_plots        : INFO     Found 1 valid plots, total size 0.09896 TiB
2021-08-07T10:04:54.512  chia.plotting.check_plots        : INFO     1 plots of size 32
  • Flax version 0.1.0.

EDIT SOLVED:
I got my answer on Discord that flax is only for OG plots.
Still it confused me since NFT can be loaded and checked in Flax.

I see this guy had a same issue on Chia:

https://gitmemory.com/issue/harold-b/bladebit/7/884376503

I checked a little through flax explorer and did not found any blocks won by NFT plots.
Maybe I did not look well enough or maybe the answer is that Flax can’t win blocks with NFT plots.
I’ll update when I find out.

I got my answer on Discord that flax is only for OG plots.
Still it confused me since NFT can be loaded and checked in Flax.