Blender File Link I have been rigging a mushroom character having hands.The model has a mirror modifier. When I'm assigning weights automatically, in non-mirrored hands,i.e left hand, weights assigned well but also assinged weights of right hand in left hand bone. Whenever I move Left hand bone it moves both the left and rights hands. I flipped names,recreated armature from the beggining but the result is still the same.
What you need to do is apply the mirror modifier. Then you can re-parent the bones to the mesh with automatic weights with no problem. Hope this is the answer you needed.