We've received reports of some pets not casting spells that you would expect them to. What we've found is that when pets spawn they are currently only receiving spells within their ability to cast them. For example, if a nightmare spawns with really low Magery it will only receive the spells that it can cast, forever, and will never be able to cast higher-level spells even if it gains enough Magery to. We're looking into improving this and don't need any further bug reports for this issue. Thank you!