SCCM Feature Update failures when UpdateServiceUrlAlternate points to localhost:8005 – is bypassing delta downloads a supported approach?

We are deploying Windows Feature Updates (23H2 → 24H2 / 25H2) using Microsoft Configuration Manager (SCCM).

On affected devices, the following registry configuration is present:

HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
  WUServer                 = https://<SUP>:8531
  WUStatusServer           = https://<SUP>:8531
  UpdateServiceUrlAlternate = http://localhost:8005

The SCCM client configures this alternate service URL when delta/express downloads are enabled. Windows Update then attempts to download update content through a local listener on port 8005.

On several devices, port 8005 is not listening (netstat -ano | findstr 8005 returns no output), and Feature Updates fail with errors such as 0x80240440. The same deployment works on other devices where port 8005 is active.

Feature Update documentation does not explicitly mention delta or express downloads, and delta appears to be a delivery optimization rather than a Feature Update requirement.

Questions:

Is it expected and supported behavior that Feature Updates can fail if the local delta download endpoint (localhost:8005) is unavailable?

Is disabling delta/express downloads for Feature Updates and redeploying full content a supported and recommended mitigation in SCCM?

Is there any Microsoft-recommended method to monitor or remediate SCCM clients where the localhost delta endpoint fails to start?

We want to confirm the supported remediation path before implementing a wider change.