Yeah, this one's common. The printer uses ink from the bottles for initial setup and regular maintenance, so the physical tank level isn't the only factor. All four ink colors need to be available for it to print—if one is low, it'll stop you. Also, printing infrequently or using mostly one color can make the estimated yields way off.
Make sure you're using the genuine Epson 522 ink bottles. Non-genuine ink can cause problems that aren't covered by the warranty.