This is normal and highlighting areas of overexposure. FYI, when you talk of default display setting, unlike many cameras where this is a menu setting, with the RX-100 the last display mode selected by pushing the top of the wheel 'DISP' during playback, remains the default until changed. You may prefer the standard view (full image, no overexposure warning). Just toggle through until you find the playback mode you prefer. there are only three. It took me a while to figure this out. PS: you made a great camera choice. As its many reviewers will confirm. One tip for truly improved photography: when indoors, always angle up the flash with your finger to use as a bounce flash. You will be astonished by how much better your flash photos look. (Assuming a reasonably light colored ceiling and shooting in portrait mode this way can be a bit less successful).