Where the check never happens
Once a unit is entered incorrectly, nothing afterward is designed to catch it. The barcode does not know the log is wrong. It only confirms that a code matches what was written down. Staff are not asked to check the entry twice, and the community rules that came with this pickup system were never written to require it either.
The responsibility for catching this kind of error does not sit anywhere in particular. The courier's job ends at a signed handoff. The management company's job ends once the parcel is logged. The app itself was built to trust whatever was entered, not to question it. Each role is doing exactly what it was defined to do, and the one checkpoint that would have mattered, confirming the unit actually matches the resident, was never assigned to anyone.
What gets missed most is the moment of discovery. The only way a resident catches this is by noticing that two systems disagree, the courier app says delivered, the building app shows nothing received. If the resident has forgotten they ordered something at all, the parcel can sit with the wrong household for weeks before anyone thinks to ask.
EVERY ROLE DID ITS JOB. THE CHECK BELONGED TO NO ONE.
THE GAP
If the parcel carried its own scannable code, checked against the log automatically at handoff, the single point of manual entry driving this entire failure would disappear. That check simply was not built in. Most parcels still arrive at the right door, and nothing in the system is set up to notice the ones that do not.
Quotes represent each party's likely position, not verbatim statements.