Can a skittering mask Step while within difficult terrain? I can't figure out if it's simply using short hand for "doesn't provoke reactions" or if this OBJECT should be treated like a character and thus prohibited from Stepping in such situations.
I mean it says Step. It even uses the capital letter.
And Step says you can't Step into difficult terrain.
One point of clarification, Step prevents you from stepping into difficult terrain, not out of. So the most correct answer to your question is "Depends on what the square you're moving into looks like" since being within difficult terrain doesn't matter.