I have now found my nemesis in pole. The Wrist Sit.
We've just learned it in level 4, and I can't quite manage to get it down consistently. Up until last night's class, I was unable to hold it for more than a second before I started spinning and losing my grip with my top hand.
After much debate the week before with the girls in my class, my instructor took some time in class to figure out what was wrong with me. I thought the problem was with my top hand not being in the right place. We tried different ways of gripping, but nothing seemed to help me be in the pose long. Then I explained where I put my hand underneath me to create the anchor. That seemed to make the difference. I wasn't creating enough of an anchor underneath myself with my wrist (hence the wrist sit) and it was causing me to move and spin.
I managed to do the sit several times in class last night, failures and successes abound. Now that I know what the issue is, I will definitely be working on that so I don't have to think about it as much.