Each CurOp is meant to store a snapshot of its opCtx's lock stats taken at the time of the CurOp's creation. These snapshots would then be used when retrieving the stats for a given sub-operation to subtract out any stats recorded by its super-operations.

However, the snapshots are never actually being taken and stored properly, so this subtraction is never occurring. As a result, all sub-operations report lock acquisition stats made by their super-operations.