Seems like an obvious case of "shades of grey" vs a binary thing.
Most people don't blatantly lie and claim they were the CEO of Apple. But does a random mid-level engineer at Apple slightly exaggerate their role on a team during an interview? Subjective, but likely very common.
Plus, many jobs are almost intractable to appropriately assign value to. If you were one of 5 people pitching a deal to a company, and it works, who's to say which person was the key to success? All 5 people might truly believe that they were the reason the deal closed and take credit for it in future interviews.