I've been having a couple problems with Summon Spider.
1 - Spider never showed up during the very first fight in front of the newbie dungeon. Combat log said it was summoned onto the battlefield yet it never showed up.
2 - After that first fight, the spider has been appearing as it should however, if the spell is not used in the first turn, often times the spell icon will become unavailable for every turn after that, as if it had been used.
Yes this is a common one.
Another one that we used yesterday was the Boulder Bash I think it's name is. It has a fairly nice area of damage. And when you put it over a group, it highlights who it will hit etc. However in reality, what I'm seeing the Area Of Damage is very much smaller, to the point now I treat it as a single target and drop in straight center on the main baddy I want to deal damage to. Now the new ground animation with that is great. Perhaps a quick check on that one.