SAN FRANCISCO, Sept 2 (Reuters) - The U.S. National Labor Relations Board is investigating two cases filed by Apple Inc (AAPL.O) employees against the company, records on the agency"s website show, amid a wave of employee activism at a company known for its secretive culture. The cases, filed on Aug. 26 and Sept. 1, are being reviewed by the agency"s Oakland, California, office. "We take all concerns seriously and we thoroughly investigate whenever a concern is raised and, out of respect for the privacy of any individuals involved, we do not discuss specific employee matters,” Cupertino, California-based Apple, said in a statement. Ashley Gjovik, a senior engineering program manager at Apple, told Reuters that she filed the Aug. 26 charge, which cites harassment from a manager, reduction of responsibilities and increases in unfavorable work, among other complaints. The NLRB investigates all charges it receives. In the event it finds a charge has merit, it prosecutes a case against the employer. Employees in Silicon Valley, especially Apple workers, are known for avoiding publicity, reflecting companies" desire to keep new products tightly under wraps. In recent weeks, some current and former Apple workers have critiqued company culture on Twitter with the hashtag #AppleToo. U.S. law allows employees to openly discuss certain topics including working conditions. In addition, workers have engaged in a heated debate on the messaging platform Slack about Apple"s move to scan U.S. customer phones and computers for child sex abuse images, Reuters reported. read more Gjovik told Reuters that after Apple began investigating her complaints, as well as allegations of sexism, her managers began re-assigning her work to colleagues and loading her up with undesirable tasks. The company placed her on paid administrative leave in early August. She said Apple had not finished its investigation. Gjovik said she has been encouraged to see more employees speaking out about the company"s culture in recent weeks. "The biggest obstacle for making progress at Apple is the culture of secrecy and alienation," she said.