In SERVER-81381, we added logic in waitForReadConcern for the resharding aggregation query to wait lastStableRecoveryTimestamp to pass the snapshot read timestamp. We also do checkpoint in the waitForReadConcern code and it requires Global-IS lock. By default, acquiring Global-IS lock also acquires RSTL-IX. Because checkpointing is not interruptible through opCtx, a slow checkpoint can block stepup/stepdown, especially in slow environments like Windows Debug.