The fact that 72 dpi helps one elevation but another still errors suggests that the failing view contains a specific texture or raster-heavy element rather than this being only a global Publisher setting.I would duplicate the failing elevation, disable surface texture fills ...

Because a single sheet exports as PDF/A and the same grouped set worked in AC27, this looks more like an AC29 Publisher regression than a general PDF/A setting issue. I would test a new Publisher Set with only two simple layouts, saved to a short local path, using the same P...