Doctor M said:
They look more like a flaw than intentional effects.
Definitely agree.
I would rule out the standard procedure of washing and reusing animation cels (a cost saving measure) being involved in such an anomaly. If so, it would affect other colors. However, I don’t see it on the adjoining skin. More likely there was some other-color reside (or too much water) still on the brush or in the paint container to affect green painting across a group of cels.
Does anything show immediately before or after this shot, but nowhere else, for just this color?