Pfizzy, im at work so i cant view the replay bro.  I have a couple questions for you though.

1.  Do you hear the shield sound?

2.  Is it just the shield animation thats not working (ie occulus doesn't look like he's shielded but he is)

3.  Were you around the sedna when it happened?  Sednas stun if cast at the same time as shield will stun the shield and you will hear the sound but it won't go off.

4.  Did it just occur for this game or for all games?

If it's for all games, or if #2 is yes then i recommend reinstalling bro.

j

1.  well thats a problem, i don't know if you are getting the cast off.

How do you cast shield, do you click on the icon then the person?  If you do, then that would definitely cast it.  However, thats not the best way to cast.  The most efficient is to use the #1 on your keyboard.  The downfall of using the #1 is the cadence between hitting 1 and then left clicking.  There has to be a pause between the 2 actions otherwise it won't cast at all.

2.  Casting shield I & II will clear a spit, but if the spit occurred at the same time or afterwards then *i think* it will be there after the shield wears off. 

3.  Shield usually trumps grasp, the only time ive had problems is with sedna's silence. (at least LE and Rook etc. have animation wind-ups)

4.  see if persists in other games, if not, problem solved lol..

5.... it could be, but i've rarely noticed a problem.  (unless #1 above uis causing the problem)

good luck bro, let me know how it turns out.

I never have had this issue and I play oak way to much. Sounds like a really weird bug.