Short answer. Possibly. Article 291 punishes a manager, employee or servant who, in that capacity, learns the secrets of his principal or master and reveals them. Three things have to line up: the position held, that the secret was learned through it, and that it was in fact revealed to someone.
What the law says
any manager, employee or servant who, in such capacity, shall learn the secrets of his principal or master and shall reveal such secrets
Revised Penal Code, Article 291 — Revealing Secrets By Employee. Read the full provision →
The article in its own words
Article 291 imposes its penalty on any manager, employee or servant who, in such capacity, shall learn the secrets of his principal or master and shall reveal such secrets. Each phrase is doing work. The accused must hold one of the named positions. The knowledge must have come to him through that position. And there must be a revelation — the article punishes disclosure, not the mere holding of confidential knowledge, and not an intention to disclose that was never acted on.
"In such capacity" is the usual battleground
The link between the job and the knowledge is what turns an ordinary indiscretion into this offence. Something learned as a friend of the family, picked up socially, or already circulating outside the workplace was not learned in the capacity the article describes, however awkward its repetition may be for the employer. Establishing that link is the prosecution's task and it is done with evidence about the person's duties and access, not with an assertion that he worked there and therefore must have learned it at work.
Not everything confidential is a secret
The article does not define what a secret is, and that gap is real. Information the employer would prefer kept quiet is not automatically within it, and material already public cannot be a secret at all. Note too what this provision does not require: unlike the companion article on industrial secrets, it does not on its face require proof that the owner was prejudiced. That difference in wording is worth attention, because it means the two provisions ask different questions of the same facts.
The criminal route is one of several
An employer in this position usually has more than one avenue, and they proceed independently: the employment consequences of a breach of confidence, any contractual undertaking the employee gave, and the criminal provision. They have different standards and different timelines, and a step taken in one can affect another. For an employee facing an accusation, the same caution applies in reverse. Either way the evidence is the disclosure itself — what was said, to whom, and when — so preserve the messages and note the sequence before memories harden.