From the best I can figure out, its not a bug, but rather a "feature" of Cross-Save. You now have a PC account that can be accessed on a console, so everything in your inventory has a PC ID tag, which can't be traded to a Console Account.
Personally, I feel like this was the dumbest mistake that DE could've made. I can't trade with over half of the members of the small clan I'm in, they either don't want to have a PC account or have no interest in PC gaming.