It sounds as if the Caran d'Ache paints are more like watercolor or even acrylic gouache than true gouache.
Traditional gouache (just about any brand) disturbs easily with even the lightest brushwork on a dry layer. However, as bad as that sounds, it can really work to your advantage once you learn to use it. It's easy to blend edges so that there's a gradated color change for instance. Or with leaves, you can put down a layer of yellow then follow it with some green or even blue or black and have a realistic leaf with light and dark. A sort of dabbing stroke is probably the most effective to use after a layer is put down with a light stroking to blend in places.
I won't lie and say this is easy to accomplish but it's very worthwhile to practice to achieve certain looks in your paintings.
You might also take a look at the paintings of Lena Rivo (https://www.lenarivo.com/
) or just search for gouache painters to see how others handle the medium. It's very versatile & can either be super realistic or more painterly/impressionistic.
Does this help answer your questions?