All that is required here is a total power down. Cures the problem. I had the issue and so did a friend. Complete power cycle later and problem is gone. You should always do a complete shutdown anyway after a new firmware install. I don't know why the PS4 doesn't do it automatically. I'm pretty sure my 360 used to do it after firmware updates.

Hmm, I have kept it off since last night. I'm about to play it and see. Will report back!

Well, I put mine into standby and the light is currently off. Getting a little worried now.

It happened to me last night the second time i put it in Rest Mode, when i put it in rest the first time after the update it was fine, but the second time the yellow light just kept flashing and i had to hold down the power button on the console until it beeped, i turned it off after that so i don't know if it's back to normal now.

I had to unplug the cord to solve it, not solving with hard reset.

I'm not sure how this bug for such a commonly used feature slipped through. I hope we can expect a hotfix in the next few days.