Not sure if this has already been reported and I couldn't figure out how to report issues, so I thought to post it here. This has been happening to me more an more frequently lately, and it isn't just colored squares! In this one instance the text began repeating itself over and over! So far it has only been an inconvenience, but for bigger projects this could become a more serious issue. Not sure if it is something that can be fixed or a programming issue. It happens most frequently with text layers or when duplicating or merging layers.