What level of difficulty are you playing?  Brad said that on lower levels he has the AI programed to make mistakes.  It is possible for the program to roll snake-eyes 4 times in a row.  Unlikely but possible.

I don't think campaign has difficulty....maybe it's defaulted to Normal.

But, I just entered into that VERY battle and the EXACT same thing happened to me with the Web spell.

When the spiders proceeded to cast Beguile spell, it was spread around my party in an acceptable manner.

Yes I did notice the beguile doing the correct spread around, but it still decided to beguile my ranged unit which does nothing...

Webbing the range unit wasn't the problem... it was the 4 times (all we successes by the way)

@you28: No. All spells go onto the stack at the same time and they all leave the stack at the same time. After the first successful web, all others are completely redundant. It's not a bug. It's more of a lack of AI; most likely to be addressed in a subsequent update.

@parrottmath: For me, some of the beguiles were successful, yet different targets were still chosen each time.