We are aware that the Friese companion unit in the story event, A World United, was wrongly set to equip dual platinum shields. This setting is not intended. Regular Friese unit (which you can get from summoning) is not affected by the wrong setting and, therefore, is unable to equip dual shields. However, she is capable of dual wielding one-handed weapons.
We apologize for any confusion this has caused. Thank you very much for your understanding.