Are those cards New, and never been studied before? Or are they already introduced cards in Learn? For example, if you look at the screenshot in this comment – Anki unable to pickup up new cards at RANDOM order - #20 by azaz44 – that user is going to see hundreds of Learn/Relearn cards before they see any New cards. Learn/Relearn cards are in order based on when they reached the end of their step delay, so once they are available to study, their order is set.