Aborbs not working

My Vengeance DH seems to be having trouble with shields not absorbing damage. I have spent over 6 hours testing and troubleshooting this issue since I recently became aware of it. All of my meters ( Details and Warcraft logs) are showing that most if not all of my shields are going directly to overheal by not being used up during their duration. Instead all the damage goes directly to my hp which is then healed back by my healing abilities. According to warcraft logs this issue goes back as far as mid 8.2.5. This was also confirmed by meters and logs of other players, not just my own.