1) No. You have not seen that. 2) No. It is not confirmed by anyone - because its not true.
But yes, it is a widespread internet myth about large MPIX cameras.
Actually WE have confirmed that high megapixel cameras ARE problematic when it comes to shake. The issue has more to do with photosite size since a higher megapixel count is being put into the same small Full Frame sensor (i.e. Canon 5Dsr). You simply need to use a higher shutter speed to counteract the less light input to saturate each pixel, motion blur due to sensor readout time increase and the higher inherent noise of Canon's high megapixel count sensors.
The direct comparison of a Fuji GFX-100 vs Canon 5Dsr is striking because of the larger sensor size and the larger individual photosites. The GFX-100 is an OUTSTANDING CAMERA that makes much better images than ANY current Canon camera! ....BUT.... I still like the 5Dsr more than the Fuji because of it's more comfortable grip and intuitive ergonomic feel in my hand. I would LOOOOVE to have a larger Canon 1Dx body with a Fuji GFX-100 sensor in it.
And right now, only one company will be coming out with such a beast and it ain't Canon OR Sony OR Fuji!