There is a relatively new bug that came along with the Rise of Iron which causes your Force Barrier to be completely stripped, essentially wasting your melee charge.
If you activate your Force Barrier when you are inside a Ward of Dawn that has the Blessing of Light buff activated, when you leave the bubble, it will strip you of all overshields. When you step outside the bubble, you will have absolutely no overshields whatsoever.
Furthermore, by activating Force Barrier (by punching a dude who has no business trespassing in your bubble) and exiting your Ward of Dawn, you are essentially wasting your melee charge. Force Barrier will activate, your melee charge will be consumed, and then your overshield will be stripped.
This happens in both PvE and PvP. Another issue with this glitch is that Force Barrier has special modifiers on it, like Gift of Light and War Machine, which Blessing does not. So while you can just step back in the bubble to obtain another overshield, you lose out on the added functionality of Force Barrier.
Do not melee kill enemies who are inside your Blessing of Light bubble unless you don't mind wasting your Force Barrier charge. This is not an issue with Armor or Weapons of Light, only Blessing. This bug is nothing game breaking, but it is obnoxious.
Source: Video by Sliq111