On the Keypad below the "Num lock", the number 8 does not function in the pattern menu.
Checked on MPT v1.17.02.28
It works in the latest beta build, but I think its more a question of just making it work using the key preset manager.
I don't think this is a bug, and therefore closing this one. If you think its a bug, feel free to respond, and we'll open it.