[LintMan]

Robotiod factories and computer facilities currently stack, but it's reported that the next patch is changing the factories to not be cumulative so computer centers might also be changed.

I don't think that nature shrines and the other planet-value boosters are cumulative.

I don't know about the combat ones.

Malfador said that this sort of information would be added to the descriptions for the facilities and stuff in this coming patch, so hopefully we'll find out soon!