I wrote this build plan which runs a "fast" step (10 seconds) and a "slow" step (120 seconds):
{F1691190}
Before the patch, running this build plan held the lease on the "fast" machine for the full 120 seconds, then released both leases at the same time at the very end.
After this patch, I ran this plan and observed the "fast" lease get released after 10 seconds, while the "slow" lease was held for the full 120.
(Also added some `var_dump()` into things to sanity check the logic; it appeared correct.)