It doesn't look so atypical to me. There are 2 random targetting effects at work: one is which center target square the spell hits, and the other is which 5+ areas are affected around to the target. If the spell precision is 100, that should guarantee the first part always hits the target square. The second randomness is what failed you, since you only get a random set of 5+ squares around the target, apparently NOT guaranteed to include the target square. In this case, you targetted "*" as the spell effect center, and the 5 affected squares were "#":
Code:
17 _ _ _ _ _
16 _ _ _ _ _
Y 15 _ _ * # _
14 _ # # _ _
13 _ # # _ _
4 5 6 7 8
X
It would seem intuitive to me that such a spell would always affect the "center" target square, but in my experience it's not uncommon that it does not. I have seen castings of bless where the affected squares seem to walk out in a line 3 away from the target, or encircle, or otherwise fail to touch any of the sacreds I placed neatly together there within range. If you can't use the battlefield-wide bless, I recommend the sacreds "hold and attack" and the blessers take 2 rounds of bless to increase the random spatter coverage. If the first bless works completely, the casters will then go off-script, which can be dangerous for holy and other path casters.
Sill