It isn't beyond the skill set of the software coder to design a PCN issuing system which doesn't allow a PCN to be issued when it isn't lawful such as when only one contravention has been committed. There isn't, of course, any money for the council in such a move. There is reputational damage but councils seem to be more interested in revenue raising than what people think of them.
Today Mr Mustard goes north of the border to Edinburgh where they don't know parking law. Here is an extract from the Adjudicator's decision in the case of Mr S
Point 1 is trite law.
The adjudicator then rubbed the council's nose in their actions