First, I wouldn't call him a scammer because its bounty managers job to choose a good translator for the project he is working for. I agree that he is unprofessional towards his work (after checking FilipeHenriques report) but IMO neutral feedback is sufficient in this case unless he is cheating by using translation tools.
I think what he is doing is something like this: He first jumbles up and adds on words here or there in English translation and use google translation tools to translate the thread.
For example:
This is from Original ANN Thread:
Dynamic block reward
Block reward is based on block height and difficulty so there is no cheap to mine blocks. That's a good thing for price stability.
This translator translates the above as:
de bloco dinâmico recompensa
bloco recompensa é baseada na altura do bloco e dificuldade para que não haja barato para blocos de minas. Isso é uma coisa boa para a estabilidade de preços.
And Google translate gives us the following translation:
Block dynamic reward
Reward block is based on the height of the block and difficulty for there to be no cheap for blocks of mines. This is a good thing for price stability.
I will add a neutral feedback towards as unprofessional work since it is limited to only low quality content and I am not quite certain that he used any translation tools. IMO low quality translation is something that bounty managers should worry about so at the moment I suggest you to report him to bounty managers.