I doubt it has anything to do with Hijack. I'll bet it's just the player software not allowing it to stay in standby for longer than 20 minutes. Not sure, though.

It's important to figure out whether it's Hijack or the player software. The way to find out is:

1) Install the player software, pure, without hijack.

2) Put the player in your car.

3) Turn off the ignition so it goes into standby mode.

4) Wait 40 minutes, then go back to your car. Light still blinking? If so, then it's Hijack. If not, it's the player software.