I am playing an umodded game of ES2 and have just researched "Climate Engineering", which lets me build the "Punctuated Evolution Foundation", a non-unique system improvement.

I am able to queue this improvement in some of my systems, but it simply doesn't show up in a couple of them.

OK, but I can terraform to fertile, which I am currently doing, so I could then see the improvement to build when the terraforming is done?

Test it? I'd guess so.