That mean the smoke detector need to be tested. Push the button for testing and the light, after, will be a hard green, no flashling.
Not if it is a photoelectric smoke detector, which is the only type you should have unless you got a good reason for ionisation smoke detector.
The blinking is the smoke detector checking for smoke particles.
photoelectric detectors use infrared LEDs. and they are inside the detector, shielded so stray light will not cause any problems.
Any red LED you see on a smoke detector is for statuses, not detecting
Thank you for the correction, you’re right. I got it mixed up with the status LED that some/most(?) smoke detectors have that will periodically blink to show that it’s active.
Regardless, a smoke alarm blinking red is to be expected, and doesn’t mean that it needs to be tested. Most of them will make a loud ping to notify the user that it requires attention, as you can’t expect people to notice the blinking LED alone.