shayla on nun pshuta
The magiya was trying to erase problematic tagim on the nun, and by mistake erased part of the rosh. Now it is a question of tzadi pshuta - the question should be resolved by a shaylas tinok. I admit that this question cannot be decided by a pic from the scan, any slight variation in size/color etc, changes the shayla - only can be decided by sight of the letter itself.