It seems not to be the solution I had hoped... My 'fix' seems to work if you're loading into ESSB, but if you then leave the immediate area (i.e., the autogen 'unloads') and then return (i.e., require the autogen to reload)... then lots of buildings are missing again.
With nordic procedural buildings uninstalled in content manager, though, everything works fine.
Hopefully someone / Asobo can find a fix for this issue soon.