Also I have noticed a handful of really small blocks that get mined especially fast. Is this just a coincidence that my lizard brain makes a connection, or is there some causality there?
Usually it's because 2 (or more) block mined within very short interval, which makes
1. Mempool empty (take note transaction propagation isn't instant).
2. Pool construct empty block (which only contain coinbase transaction) while waiting verifying previous block and removing transaction on mempool which already confirmed.