An applicant or employee subject to this subtitle may file with the head of the principal unit a written complaint: that alleges a violation of § 5–208 of this subtitle; or that alleges harassment in violation of § 20–606(a)(5) of the State Government Article. A complaint under subsection (a)(1) of this section must be filed within 1 year after the complainant first knew of or reasonably should have known of the alleged violation that is the basis for the complaint. A complaint under subsection (a)(2) of this section must be filed within 2 years after the alleged violation that is the basis for the complaint.