In the manga Death Note, when Misa meets L for the first time, she has the shinigami eyes, so she must be seeing L's lifespan at the moment. L dies a few volumes later, so couldn't Misa have alerted Kira that L was about to die, and it wasn't worth much trouble?
Is this a flaw in the manga?
It might also be the case that since L was killed by a shinigami itself, the lifespan Misa saw with her shinigami eyes didn't account for that death.
Which of these possibilities is correct?