No specific examples will be given, as the specifics here aren't the point. I'm also not talking about consequences of holding objectively false beliefs, nor in communicating them (knowingly or otherwise). I'm talking about whether unknowing self-deception (by continuation of holding the belief, not necessarily by origin) should be understood as a harm to oneself.
To clarify, I'm not asking if a belief can be harmful (as incapablei.e., capable of causing harm), but rather if it can itself be a harm per se. Is holding a belief in something that is objectively false itself inherently a harm?