No, I don’t know the answer, Ramesh, but I’ve noticed the same thing.
The couple of times I’ve felt like saying something about abortion, I’ve trawled through the polls available on the internet, and they are all over the place.
Granted, this is a topic some people think & care about a lot, most people–surely most men–not at all. So a lot of people might give you a different answer on Tuesday from the one they gave on Monday.
(I am probably one of those people.) Still, you’d think pollsters would have techniques for clarifying the fuzziness.