So I have just ran into this as I was just given access to the feature on the website.
I had my PC account Linked as primary to my switch and xbox accounts, and I now cannot access the Jade cosmetics on my xbox. This is likely the same outcome for the Switch skins.
The website stated, and I quote:
"Platform exclusive Skins like Opal Skins on Switch, Amethyst Skins from Discord and Jade Skins on Xbox will not transfer to PlayStation during the One-Time Account Merge. In addition, PC exclusives such as the Phased Skins, Rubedo Skins, IAHGames Braton Skin and Rixty MOL skin will not be available on PlayStation. Conversely, PlayStation Obsidian Skins will not be available to use on platforms other than PlayStation."
However, nothing was mentioned about said skins being unavailable for accounts where PC is primary.
Was this intentional, and am I now just out of the money I spent on xbox for these Jade bundles? If so, please spread this information so everyone else is aware.