It’s not because of controversy - IriShim are hand colored for each color, which is why they’re only on Moderns (since they have to share the same gene options). Ancients don’t get it because it would take too long to do, and Ancients whole purpose was a less intensive work around to allow regular breed releases.

You may be thinking of the IriShim controversy regarding the slightly different styles between the old/new color wheel (new colors have more intense highlights), but that is more so regarding whether staff is ever going to adjust those for consistency like they’ve said.