Most of those words are also recently added some days ago which may be why they haven’t shown up quite yet. As Phil mentioned, the word selection algorithm will try to focus on “broad character coverage” (i.e., getting an even character-distribution in the words selected), which is why this may not have shown in your queue quite yet.
As we start adding more and more lower-level HSK words, we are also looking into potentially adding an option for users to change the word-selection algorithm to prioritize words based more on HSK level than “character coverage”.