According to the pager, which has good internal connections at Samsung, it's been confirmed that the corporate is indeed working on a 600MP sensor. To prove that, the informant published a slide that is part of the internal documentation or presentation.
The slide reveals a lot of information - from some of the main specifications to the motivation that led to the implementation of this project. It is pointed out that as 4K and 8K video recording becomes more accepted, Samsung wants to cover it with a larger sensor, which allows video zoom without compromising quality too much.
An ISOCELL 600MP sensor with a 00.8µm pixel size, however, is not expected any time soon, as Samsung has to find a solution to bulge the camera. A 1 / 0.57 "sensor would take up about 12% of the phone's back panel, with a bulge about 22 millimeters in size.