Around 1 % Incorrect shares and lower hashrate than expected

Hello,

I am mining with 30 MH/s with Claymore on windows, but I have around 1 % incorrect shares and the displayed hashrate is much lower. I mined on nanopool before with my exact same settings and I never experienced these two issues.

Any thoughts ?

ETH address: 0x56C9fA4038d721E386602CEDB5FeED650A035346

Thanks and best regards,

Stephane