portfolio sort repaints the screen twice

I am seeing odd behavior on this page. Click on a category, and the page redraws — then the images fly off — then the page redraws again.

How can I fix this so the images do not fly off and then return?

http://wp2.decisionneurosciencelab.org/people-portfolio-test/ (use password wp2 to view pages)

I am migrating from another theme – rt-17 – residual data from which might be causing this problem? Live site is here: decisionneurosciencelab.org