No that's normal now that you are outside of Wizard City (wc). As you progress further to other realms you will see more and more of this. Wait till you get to Dragonspyre (ds). The next world you get to will be Marlybone (mb) and you will start to see monsters marked as one school but with a natural attack from another school. ;)
Don't assume I'm a new Wizard101 player. I have wizards in DS, Mooshu and Krokotopia. And I made no mention of his physical (natural) attack.
Yes, I'm aware that all monsters can cast cards from several schools other than their own. But when it comes to traps and blades, they keep to the school that they are from.
The Sokkwi Ripper is labeled as being Ice. Yet, they cast Myth traps. This tells me that KI has mislabeled them as Ice when it should be Myth. This isn't the first time something like this has happened considering that our Oct 16th patch fixed a similar problem when the O'Leary Rowdy were mistakenly labeled as Storm, but should have been Ice.