Witnesses on the flotilla confirmed it was a drone and footage obviously shows a drone dropping something.

https://www.bbc.com/news/live/cwyd3vxdgx1t?post=asset%3A845bc090-a4f9-454c-86ff-5ffe5c919cdc#post

They said it was “very difficult to say anything definitive” from these images. “It is entirely possible that this was a round from a flare gun hitting the vessel. This would explain why it appears to fall onto the ship at a very slight angle… and the source of the light that it is emitting,” Sibylline told BBC Verify.

They say that the noise in the video could come from the Family or a nearby vessel. It may well be some kind of drone but “it could have been… capturing footage for social media”.

Sibylline say the scale of the damage also throws the drone allegation into question.

“It appears to have been a small fire causing relatively localised damage. A kamikaze drone or a grenade dropped from a drone would likely have done more damage,” the firm said.