If IPv6 reputation is done at the /48 level but you have, say, a /56 then you're sharing reputation with up to 255 other customers.
I ran into this problem 15 years ago or so when I built my own ipv6 tunnel for home use using a hetzner server. Couldn't edit on Wikipedia, asked why, and apparently they blocked a whole /48 because of spam. Then they argued the whole provider should be blocked because it's a "tunnel provider" (it isn't) at which point I didn't even want to argue anymore and just stopped editing.