Currently the internal tables used for index builds are dropped with a droptime of Timestamp::min(). This is invalid, as untimestamped drops should only be used for rolling back table creation, and results in the drop being unreplicated. It should instead use the optime of the commitIndexBuild or abortIndexBuild operation that's causing the tables to be dropped.

KVDropPendingIdentReaper currently has a workaround for this (enableDeferUntimestampedDrops()) which should be removed once this is fixed.