Nonmagical weapon bug

[Fermouth]

Obvious exits: north, east, southwest
[HP=383/MA=190]: (Meditating) a ter
*Combat Engaged*
[HP=383/MA=190]:equip oaken staff
You have removed skull-capped staff.
You are now holding oaken staff.
You are extremely quick and deadly with this weapon.
[HP=383/MA=190]:a big terror beast
Your weapon has no effect against this monster!
You smack fat terror beast for 16 damage!
You critically whap fat terror beast for 89 damage!
You critically smack fat terror beast for 85 damage!
You whap fat terror beast for 16 damage!
You swipe at at fat terror beast!
The fat terror beast swoops down and bites you for 26 damage!
The fat terror beast swoops down and bites you for 12 damage!
The fat terror beast swoops towards you, but you dodge!
The big terror beast swoops towards you, but you dodge!
[HP=345/MA=190]:
Black Wasteland
Also here: fat terror beast, big terror beast.
Obvious exits: north, east, southwest
You critically smack fat terror beast for 81 damage!

[Gardner Denver]

sigh.  1 step forward, 19 steps backwards.