As employer never made working on leave a condition of employment or threatened employee with adverse consequences, lack of assignment of the employees duties to another in the interim did not interfere with the exercise of the statutorily guaranteed leave.
The distinction between actual due dates and horatory due dates presents a genuine issue for trial on the claim of pretextual basis for retaliatory action.
State law whistleblower claim would require an actual violation of state law, not merely discusion of an illegal practice.
https://www.ca5.uscourts.gov/opinions/pub/20/20-30289-CV0.pdf