FreeOrion

There is some strangeness when Sly colonize a planet with the Gaia special.

1. At present the planet cycles through the planet types never stopping. Clearly Sly will never reach good suitability on a non-gaseous planet.

2. When evaluating planets for Colonization, the AI presently treats a Gaia special as favorable for Sly, even though Sly receives no benefit from it.

Exobots also receive no benefit from Gaia specials. When they inhabit a planet with a Gaia special, the planet type does not transform.
The Colonization AI devalues the Gaia special when evaluating planets for Colonization by Exobots. A similar approach can be taken with Sly.

Thanks for putting up the issue #3001 (and PR)

It's been suggested before over here to completely re-work the way terraforming works. While there might be a shorter term solution I think that it's worth looking into again for the longer term.