We see the same three patterns on every project we run.
One. The contractor notifies under Clause 61.3 but doesn't reference an event in Clause 60.1. They write a paragraph about why something is unfair and call it a CE. Under NEC, that's a complaint, not an event. The Project Manager's only honest answer is "this is not a compensation event."
Two. The notification arrives after the eight-week window. Under 61.3, late notification means the contractor loses the right to claim — barring narrow exceptions. We've watched contractors lose R3M+ on a single rejected CE for a clause they never read.
Three. The quotation under Clause 62 doesn't show effect on the Prices, the Completion Date, and the Key Dates separately. One number for "the impact" is not a quotation. The Project Manager rejects on the basis of incomplete information, the contractor resubmits, and now we're outside the assessment period.
The contract is built to be administered. Most contractors don't lose CEs because the merits are weak. They lose them on procedure.
More on how NEC3 handles compensation events, time and payment in the NEC3 Contract Assistant, or see how it compares to JBCC in the NEC3 vs JBCC guide.
General guidance on how the contract works — not legal advice, and no substitute for reading the contract and its amendments on your project.