When updating a Build report, per default new cells are not selected for publishing. I assume that the standard case is to publish the whole notebook, which makes it very unintuitive and error-prone to update only a subset of available cells. At the moment one needs to select “hide all cells” and then “show all cells” before updating a notebook build report which should be published completely.
I think a good solution would be to have a second user option “publish all cells”, “publish inputs”, “publish outputs” and “custom selection”. an only if the latter is selected allow the user to select individual cells.