All the rules aren't always true with every kind of leather. While there are generally rules for dealing with leather of this type or that type, they don't always apply to every tannage falling under that name.
Again, I was kind of guessing about the leather being an oiley. I'm not sure that it is. If it is, that doesn't necessarily mean it won't take a burnish. All leather is just so different each other.
Hopefully, someone with more experience than me will chime in.