It sounds to me like it is either a knowledge gap of which they may be unaware, or a personality issue. When hiring in the past, I looked for thoughtful, but honest answers-- even if the answer was "I don't know." Someone talking around the question or bullshitting me resulted in a no. Also, interviewers may be sensing some quality which hint that the interviewee would make existing employees' jobs harder. Dunno if this is happening, but things like talking bad about previous jobs, management, etc can turn folks off. Also, if one implies many previous jobs were problems the interviewer may assume that the employee was the issue instead.