This is because of speed optimisations performed by Qt, the GUI library we use. Rather than loading the entire database before showing the card browser, Qt only loads the first entries in the database, and then incrementally loads more from the database as you scroll down.
Instead of scrolling all the way down to reach the latest cards, you can sort the table by clicking on the "creation date" column header (clicking again switches the sort order). However, this is not done by default because of speed reasons (BTW, there's a dialog explaining why the database is not sorted by default the first time you sort a database that way).
This being said, not saving the sort order of the browser was a decision made 10 years ago, and processing power has increased since :-) For a next release, I'm considering to at least at the option to save the sort order.
Thanks for the feedback!