This is not a tiling issue. I am having the same problem...my image is duplicated in all four corners, but not the entire image. I have attached a screen shot for reference. It has to do with the computer display, because this is the second time it has happened when I connect to an external monitor through HDMI. I disconnect from the monitor and the problem persists. The only way to fix it that I've found is to close and reopen as the OP notes. I feel this is definitely a bug that Adobe needs to address.