[thejeff]

I can't look at the turn right now, but when you say by himself, there's no one, including enemies near him when he casts bless?

In my tests, targeting was the problem. Bless would target any unit as long as the AoE in its tests included unblessed sacreds. Since the AoE spreads randomly it doesn't always include the same squares and the actual cast might not cover any actual sacreds.
This isn't necessarily a bad approach. If a non-sacred is between 2 groups of sacreds, targeting him might actually cover more sacreds than aiming for any of the actual targets.