bug with traps staff?

[wobbly]

Zapped an unidentified staff and a confusion trap appeared on the screen. Moved once & it disappeared. Tried it out again & it appeared on a different part of the screen. The auto-target in the look command doesn't find it & scrolling with L causes it to vanish. Still haven't identified the staff but I'm assuming it's the one that generates traps. Doesn't seem to be freedom & can't think what else would cause this. Will edit when the staff is id'ed.

Edit: It is a staff of entrapment. I guess it's no big deal other then identifying the staff for me.