Short block generation time in Cosmos

Hi all,

I noticed that around 4% of all blocks in Cosmos are generated within 2 seconds.

My first guess was that these are empty or almost empty blocks that are generated during small Mempool occupancy. Instead, independently from number of transactions in the blocks they can be generated, in general, 3 times faster than the standard block generation time, i.e., within 6 seconds that happens more than 80% of times.

So my question is what causes this fast block generation time?

I’d love to hear your thoughts.