I suspect you still have a momemtum issue in big breeze.

light boat with crew will be stopped by large waves...
so you loose your attached flow on your sails and cannot respond quickly enough with the sheet to keep the boat going.

A heavier boat with same crew will have more momentum and a greater chance to maintain some speed and keep flow attached.

Robbie Daniels who race a Tcat and raced a prototype M20 for some time reported this behavior. He wasn't sure if developments in sailing technique could compensate in those conditions for the loss of mass.