Least Dragonmark not working

[Kamenecki]

My Least Dragonmark of Sentinel on my 15lvl Human Fighter that used to give me Shield of Faith +2 to AC stopped working. When I use one of the 3 charges I get the animation but nothing else happens, no Shield of Faith spell icon in upper right corner and no bonus to AC.

Thank you.

[rimble]

Doesn't stack with Protection items. You'd think it would still activate, and not really do anything, if you're wearing a Protection +2 item or higher...but I guess maybe it just fizzles out if it can't help you.