element order and convergence

I have a FSI problem that converges when I use first order elements for pressure and velocity and second order for displacements. But I am not happy with the results I am seeing. Hence I changed the element order.

I am using second order elements for the velocity and displacement and first order for pressure. Now the problem is not converging.

It should not be behaving this way because I think that increasing the order of the element should give better convergence. Am I wrong? Did anybody face a similar problem?

Thanks,
Sirisha