Mage armor is not concentration spell it is a straight 8 hour spell. I had my mage armor lost due to losing concentration, or being downed. It is 8 hour duration spell and should not go away when knocked down, slept, hit, etc... Only thing which should remove it is anti-magic or dispel magic
I run a warlock with shadow armor and I use all my mage armor scrolls on gale and I have yet to encounter this bug. Can you include a screenshot of your combat log with this happening or a video?
