How are you resizing? Is there a fitting option applied to the frame? Is the center poxy point selected in the transformation proxy instead of the corner point you want to anchor?
Figured it out! Just as I was about to type "grabbing the bottom right handle with shift/alt/command held down" I tried it with just shift/command and it sent it to the top left corner for resizing instead of centering it. Thanks for the brainstorm!