The assumption of a malfunction was mentioned on one of the the social media accounts of the GSF and by one of the people on another boat last night during the livestream.
But you can also just use your own head. The IDF has full coverage of the entire area with drones and satellites. Nothing will get through if they dont want it to. There is no slipping by undetected or anything like that. They have thermal cameras on those drones so not even at night.

If that boat was actually ever there then it was either already captured or somehow locked in place by the IDF or it was emptied and drifted there.

My friend that works in a sea rescue org always rants to me about how Frontex knows everything going on in the mediterranean sea. When their rescue group finds a sinking boat with people in the water they often struggle to find all the people in the waves. Frontex with their drones flying above them knows about every single person in the water, but they dont share any information with civilians...