I found how to get 60fps. the setting for 1440p 60 / 1080p 30 will only stick when it is chosen with both cameras connected. if you, like I did, remove the cam from the car and connect it to a pc, the setting is lost and reverts to 30fps for both cameras, so you have to reconnect via wifi and choose the 1440p 60fps setting again. being the sd card slot is in a very inconvenient place, it is easier to remove the cam than try to remove the sd card.
this likely could be fixed with a firmware update. I would consider it a bug.
hope this has helped others.