Have the checked the anchoring on each field and their legends?
In Layount Mode, click on a object, make sure Inspector is open (ctrl/cmd+I), click on the Position tab in the Inspector and check the padlocks are clicked to the left to lock them to position based on the left hand margin. If the right hand padlock is instead clicked it will position the object according to the right margin when you save the layout and go to browse mode
you were spot on. Although the fields showed they were anchored, I removed all anchors, saved the database, reopened it and re-applied each anchor and things now work as expected.