Ok, more-or-less fixed it by fixing the form tabs; in the section for two cells
"formname":"TwoCells"
,"formtabs":[{
"caption":"Row Format"
,"fields": [{
"field":"fake"
,"inputTV":"hidden"
},{ "field":"cell_3_image"
,"caption":"Image"
,"inputTV":"hiddenTV"
},{
Needed to change the "hidden" to "hiddenTV".
"formname":"TwoCells"
,"formtabs":[{
"caption":"Row Format"
,"fields": [{
"field":"fake"
,"inputTV":"hiddenTV"
},{
"field":"cell_3_image"
,"caption":"Image"
,"inputTV":"hiddenTV"
},{
Still get intermittent bad fields in two and three cell forms, with the actual fields displayed below the resource content, but a page refresh usually fixes it.