Could be, but im pretty sure its not. There is a setting to redner a second image, that could be it. Furthermore i am not having this issue, and i cant find any other evidence.
pretty sure you have a line break after your prompt, and it is generating an "empty" image because of the empty line... happens often when you copy your prompt from somewhere etc, or press "enter" at the end
I've had that happen a few times, it happens when you accidentally leave an empty line after the end of your prompts, like if you hit ENTER one too many times, or left a line after deleting a bunch of prompts.