Change the number for a new card that has no morphs to something lower than the highest possible number: change default_difficulty = 2147483647 to something like default_difficulty = 9999999. When a card gets repositioned, and all of the cards get moved up, they wind up with a negative number, which puts them at the top of the queue. This happens whenever I reposition on Ankidroid, and today it just happened when I hit the Ankimorph "Learn card now" button.
Originally posted by @xofm31 in https://github.com/mortii/anki-morphs/discussions/167