Xbox PC Liveries Not Carrying Over This Time

Apologies if there is already a thread for this.

So, when moving from both TSW3 to 4, then 4 to 5, all the liveries I had made had carried over fine, however this time when moving to 6, they're all gone?
Has anyone else had this or know how to get them back? I don't get why they'd carry over for all over versions but not for 6...