NBminer has released a new version v39.4 which fixes the issue with rejected shares on Octopus Protocol.

Make sure you update to the latest version, which also has an extra LHR mode launch parameter.

The release changelog is listed below:

• feature: ethash new low power LHR mode, add -lhr-mode option.
• lhr-mode 2 is the default LHR mode, which is the new lower power mode.
• lhr-mode 1 changes LHR mode to old version, which is the same as v39.2
• lhr-mode 1 is suitable for only power limit bounded GPU, can achieve higher hashrate than mode 2
• lhr-mode 2 is able to achieve lower average power and temperature. especially suitable for GPUs with gddr6x e.g.3070ti, 3080, 3080ti. Power consumption is fluctuating in this mode, better to be used with locked core clock.
• feature: lhr support decimal value
• feature: for LHR GPUs, when mining lock is detected, miner will automatically decrease 
• lhr value by 0.1, and continue mining. max decrease times is 10, which sums to 1.0
• fix: higher CPU usage when set --share-check 0