Been there too many times, having struggled to get what is a normally easy boat to right and it simply won't, you think of all the things you haven't done, let off the downhaul and bingo up she comes as easy as normal.

I think its some thing to do with the mast bending back creating a tight area of sail, creating air drag. It won't allow you to get the mast perpindicular to the wind and then you get all the nearly moments you mention.

As an experiment try facing your boat directly into wind on the beach without any main sheet on, now tighten the downhaul and see what happens, you maybe surprised. Mine becomes like a cat on a hot roof, bouncing around all over the place.