There are three rules that cannot be broken, and all three concern the impulse. Breaking any of them discards the markup entirely — it is not demoted in a ranking, it leaves the output.
The three impulse rules
Wave 2 does not go beyond the start of wave 1. If the pullback ate the whole move and went further, it is not a second wave, which means the whole numbering is wrong.
Wave 4 does not enter wave 1's territory. The classic overlap rule: the fourth must not reach into the price range covered by the first.
Wave 3 must pass the end of wave 1. Otherwise the third is short in the weakest possible sense — it fails even to reach the first wave's extreme.
These three come first: if a numbering contradicts them it is wrong, however convincing the chart looks.
The diagonal rule
In a diagonal, overlap between waves 1 and 4 is allowed — that is in fact how it is identified. But the suspended rule is replaced by its own: wave 4 does not go beyond the end of wave 2.
A leading diagonal carries an additional check: the pullback must not go beyond the start of the diagonal itself.
A very deep pullback is also a reason to doubt
The wave 2 rule is formally broken only by passing the start of wave 1. But a pullback that eats almost the entire move — say 99% instead of the typical 38–62% — breaks no rule while making the markup suspect.
Usually that signals not "a very deep second wave" but a badly chosen scale: what was taken for wave 1 is in fact part of a larger leg. Check the markup one degree up before insisting on it.
What happens on a violation
The markup is discarded outright. Not "demoted in a ranking", not "counted with a caveat" — it simply stops being a permissible option.
If no numbering passes the rules, the honest answer is that there is no markup. Missing markup means the move does not fit the grammar, not that something is wrong with the chart.
Why the rules are hard
Because soft rules filter nothing. If a violation is "taken into account with a reducing coefficient", any picture can be marked up any way, and the markup stops being a statement about the chart and becomes a statement about the taste of whoever drew it.