I have two issues with specifically cosmetic evolutions:
First of all the preview for "red fire" and "blue ice" evolutions received from the season pass has suddenly stopped working on the console but is available on the web app this issue has already been addressed by another user before.
The second issue is that evolution stacking is broken or disappearing after applying as yesterday I applied "champions excellence" cosmetic on one of my hero cards which already had "heroes embellishment" evolution applied on preview it showed that evolutions would stack with there still being purple hue from "heroes embellishment" around "champions excellence" card and it was on the card immediately after applying however after using the card in-game it has reverted back to just "champions excellence" cosmetic with no evidence of having previously used "heroes embellishment" evo. Which is very disappointing as I had a unique card design by stacking those cosmetics as it was said on your FUT Deep Dive pre release that those evos would stack if they didn't overlap which was the case here as the purple hue from "heroes embellishment" wasn't overlapping with the red background given by the "champions excellence" evolution at the time of applying.