I have two Models, ModelA and ModelB.

ModelA has a One2many field to ModelB and ModelB has a Many2one field back to ModelA

I can open a wizard and add or remove lines no problem.

I also have another model which is a Transient Model that opens a wizard to update various fields relating to a Sale Order Line. I want to be able to update ModelB records linked to the Sale Order Line.

I can do this, but only if I leave at least one record. If I try to remove all the records, nothing is updated at all.