It’s because, unfortunately, bundles like the Crook are among the oldest bundles released on Roblox. Over the years, the catalog team has lost the R6 source files for these bundles, making adjustments to things like the UV harder for them to do, and there are a lot more serious catalog issues that they need to look into first, putting matters like this on the back burner unfortunately.
I did reach out to Kalgurnna about some of the newer bundles R6 variants still being held by the artist, but it’s Roblox’s decision to reach out to them or not.