There are 334,911 questions under the "active" tab, 334,914 under the "newest" and "votes" tabs, and 333,037 under the "hot" tab.
Is there a reason for this inconsistency, or is it a bug? Are there 3 questions which for some reason are not considered active and 1,877 that aren't hot?
Perhaps the lesser number of active questions is due to page caching, but that doesn't seem likely for the hot tab given the number of missing questions.