Since patch 7.32 (if I'm not mistaken a common standart belt on Shadow Demon remains on all sets. Valve still hasn't fixed it! Below I have attached screenshots of a standard set with a problematic belt and how this belt overlaps (remains) with other sets.
Cosmetic Item Name
Standard belt on Shadow Demon
Description
Since patch 7.32 (if I'm not mistaken a common standart belt on Shadow Demon remains on all sets. Valve still hasn't fixed it! Below I have attached screenshots of a standard set with a problematic belt and how this belt overlaps (remains) with other sets.
Example Match ID
6831833134
Screenshots