Does an employee's mistakenly taking a paper from a meeting, which resulted in a loss for the employer, constitute theft, and what is its expiation?

There is no sin upon you for submitting the paper first, because it was a mistake that you rectified and corrected. This is neither a theft nor a sin requiring expiation, due to the words of the Messenger of Allah, peace and blessings be upon him: "Indeed, Allah has forgiven my nation for their mistakes, forgetfulness, and what they are coerced into."