The red light flashing may be the normal working state of the smoke detector, or it may be faulty. Generally speaking, when the smoke detector works normally, the red light will flash at a certain frequency to ensure its normal work. If the red light is always on or flashing abnormally, you may need to contact the landlord or property management company for maintenance.
In order to ensure the safety of living, I suggest you know more about smoke detectors, such as how to use and maintain them correctly, and the relevant laws and regulations in your area.