World Partition Cells load but are uneven

Hi as the Heading says, so i make a World Partition Landscape, everything seems fine, i use the landscape tools to make my land scape how i like, save as always, then out of the blue after reloading the landscape some cells don’t match the height of other cells, this causing the landscape to be stuffed up, i get no errors or anything, its SUPER PAINFULL and makes World Partition completely pointless, is there anyway to get the cells the reload at the right heights again ? and why would some cells all of a sudden change height anyway,