Android : FLAG_SHOW_WHEN_LOCKED not working in latest version of 4.4.2

The main window of my app sets the FLAG_SHOW_WHEN_LOCKED and FLAG_DISMISS_KEYGUARD window flags to bring up the app window in front of the usual Android lock screen. The exact code follows

    getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);

This has worked perfectly ever since ICS on all my devices. But recently I received two reports from end users that the app was no longer coming up on top of the lock screen. We finally established that the first user was running Cyanogenmod and had him open a support issue with them. But the second user is running an absolutely stock OS. To make things even more interested, he reports that it was working properly when he first installed the 4.4 system update. But installing the most recent system update broke things. Since then our app no longer appears on top if the lock screen, but it bumps up immediately as soon as the screen is unlocked.

Technical details...

Mode number: SM-G900P

Android Version:4.4.2

Baseband version: G900PVPU1ANE5

Kernel version: 3.4.0-1750661

dpi@SWDD6020 #1

Fri May 30 21:23:48 KST 2014

Build number: KOT49H.G900PVPU1ANE5

SE for Android status

Enforcing

SEPF_SM-G900P_4.4.2_0016

Fri May 30 21:23:28 2014

Security software version

MDF v1.0 Release 3

VPN v1.4 Release 1

I do not have a phone running 4.4 yet. I run the app on the latest and greatest 4.4 emulator and did not any problem with it popping up over the lock screen.

Anyone else heard any reports of this? Any suggestions on what we can do next?