Did the animators make a mistake with Nami's glove after she stabbed Usopp at Arlong Park?
This incident occurs during anime episodes 33 and 34. Nami does not wear a glove on her right hand at any point. 

See the stills from these episodes below. 

Scene 1: Nami "stabs" Usopp at Arlong Park

Nami pretends to stab Usopp. 



Scene 2: Nami returns to her room

Nami has bandages on her left hand when she returns to her room. 



Scene 3: Nami meets Luffy's crew

Nami has a glove on her left hand when she meets Luffy's crew.



Scene 4: Nami visits Nojiko

Nami still has the glove on her left hand when she visits Nojiko.