fire exit light signs factory

This Australia standard fire exit light sign without Arrow,only running man and door,

The customer has installed 22 of these exits, and non of them have problem.

After a few seconds, the led light on the exit board will begin to flash, every few seconds.

Please see below the video, how can we fix this, is it faulty exit? Is it wiring issue, can it be resolved or do we have to send it back

fire exit light signs China
fire exit light signs China