It could be a progression film to film but both AVP and AVP-R both came out before Predators and both of which take place in 2004.
The shuriken is also in The Predator so it doesn’t have to be tied to Scar or Wolf.
We have honestly no idea what happened other than they likely didn’t have access to AVP content. AVP is a separate license and things are licensed as well as use continuity based on brand for some bizarre reason despite Predators being featured in both and the Thomas brothers believing they have claim to the AVP incarnations of the Predator character. It’s currently believed licensing was the hold up on Scar and that his assets was or will be reworked into an OC or released in some other way.
Scar’s mask was leaked but was renamed and doesn’t have the most accurate helmet model out there. Granted neither did City Hunter but it could be that they can use the iconography, just not the version from the films. So similar to how we can have a plasma pistol but not the one Wolf used.