There is a new Skip shorts switch in the list selector, alongside Skip watched and Skip ignored.
The problem it solves is arithmetic. A channel that posts one long video a month and a Short every day ends up with thirty times more Shorts than videos in your pool, so a random pick from that pool is overwhelmingly a Short. You did not subscribe for a different ratio than the one you got, but random sampling does not know that.
Watched and ignored videos have always been filtered out of your suggestions. That is the right default, and it is still the default — but it was also permanent, and it should not have been.
You can now split your channels into named lists and switch between them.
Until today every channel you added went into one pool, and a random pick came from all of it. That works until your pool contains both twenty-minute cooking videos and three-hour lectures, at which point “random” stops being useful — half the suggestions are the wrong shape for the time you actually have.