Johnny

I am unfortunately not the server host. I tried doing it in vanilla minecraft and it did work so you are right it is probably just aternos. I think we will just use commands to grant us that one achievement. Thank you for your help with everything!

So currently I am on an Aternos sever (paper) 1.21.7. I have a tamed wolf and I crafted armour for them and placed the armour on my wolf. I tried to shear the wolf while it was sitting, standing, leashed, and unleashed. Nothing seems to trigger the advancement. It might be a bug with Aternos or the paper server.