the official faq says "Are cosmetics (Outfits, Charms, etc.) transferred between platforms?

Yes, your cosmetic items will be shared between platforms. However, please note that platform exclusive cosmetics cannot be shared."

and um.. no, my cosmetics did not share from xbox to steam. For example the transparent candy halloween weapons - I don't see them on my steam account, but they r present on my xbox. Is there a fix for this? I've tried to contact support, waiting for their answer.