I've been noticing the same, and initially assumed it was maybe a low spawn, until I reached the second floor which was easily max spawn.
Another thing I noticed - about half the time I go for the bounties, one bounty is missing from any of the loot spawns, and usually a chest on the second floor has at least one broken item, which I assume was meant to be the bounty. However, when going back to the bounty board it still assumes that bounty exists.