AI models will often lie

AI models routinely lie when honesty conflicts with their goals

Some smart cookies have found that when AI models face a conflict
between telling the truth or accomplishing a specific goal, they lie
more than 50 percent of the time.

The underlying issue is that there's no right or wrong way to
configure an AI model. AI model output varies depending on the
settings applied and those settings may entail trade-offs.

https://www.theregister.com/2025/05/01/ai_models_lie_research/