[yetihehe]

So, it was observed but it did not occur? Could you expand this a little?

[Moldoteck]

Bc of travel distance, meybe they mean that it occured earlier but observed than

[yetihehe]

It did not occur at the source of event, because at source gravitational waves and light waves were probably pretty close together, so "not simultaneous arriving of light and grav waves" is an event which was observed as happening on Earth in 2017.