I dont know. Given that Israel is announcing constantly over the past days how they were hitting hundreds of Hamas targets, they claim to have a very detailled knowledge of where Hamas is. That also means that they must have had noticed increased activity, because all the material for the attack needs to get somewhere and at the latest they most have had noticed the buildup of fighters and demolition equipment on the morning of the attack.

So either they knew very well that the attack was prepared at the latest when it was imminent, or they are now lying about the targets and just lobbing bombs at random places now. But also i remember the videos of the soldiers being caught off guard when Hamas was storming their bases, which means a collossal fuckup in the warning chain or deliberate non information.