With respect, I wouldn't know if that was unintentional. I'll give my own case of when I lived in the United States. I had to go through a similar process where I had to give my history, fill out all the forms. There's an onus on the person to actually make sure not only to double but to triple and quadruple check.
When I was living in the United States, it's not my right to live in another country. I am a guest in someone else's home, and I think the onus is on me to make sure my information is correct. Do honest mistakes happen? Yes. I'm not sure forgetting to list that you were working somewhere for four months would, in my own opinion, constitute an honest mistake.