I'm also having the same exact problem, so far what "fixed" it for me was logging out of my account, making me think this is just Youtube rolling out some worse homepage to some users as an experiment.
I really hope this doesn't continue, this homepage is awful, the thumbnails are way too big making me have to scroll way more than usual.

I'm also having the same exact problem, so far what "fixed" it for me was logging out of my account, making me think this is just Youtube rolling out some worse homepage to some users as an experiment.
I really hope this doesn't continue, this homepage is awful, the thumbnails are way too big making me have to scroll way more than usual.