Early filer's are subject to IRS program glitches which are all too common every year. My educated guess is that there was something in some early filed returns that the program got hung up on so the returns were put in a "side pool" until the situation could be fixed. One of the usual "holding pools" will require human interaction to release them so those returns may take a while to be released for processing. Some returns may be issued ID verification notices some may not. Again there is nothing you can do but wait for your return to continue thru the processing pipeline or for an IRS notification to be issued.
