SERVER-132525 removed the usage of single-phase, foreground index builds for internal operations on collections under the config database (in favor of standard two-phase builds). While this allows to avoid a potential crash scenario when the build needs to be aborted, the current implementation is affected by two factors that leave room for index creation requests issued during an FCV transition or node step up to remain inflight (and possibly fail) once the parent operation is already over:

• Index builds unconditionally a CommitQuorumOptions::kPrimarySelfVote value
• Index builds are issued during a node step up in a "fire & forget" fashion