Why does the NI USB-6229's Power (+5V) LED blink after turning the device off?

[b!tmaster]

I have noticed that the green Power (+5V) LED on the front panel of the NI USB-6229 I am using blinks after turning the device off. Does this mean anything significant? I will also mention that it remains blinking for an extended period of time after I have turned it off and unplugged the power supply.

[Maxwell.B]

Has it always done this?

[b!tmaster]

I don't believe so. Oddly enough, the device is no longer exhibiting the described behavior. The light now goes out immediately after turning off the power switch.