Hey Ram,
We've identified the reason for the error. It seems that there's a disparity in updates when comparing direct GUI Windows updates versus using the Windows Update API (WUA) via Ansible. WUA doesn't seem to have access to beta version updates from Windows, which is causing the error "Unknown WUA HRESULT 2147944003 (UNKNOWN 80070643)." Unfortunately, we haven't found a solution yet. For now, we've opted to skip the particular update KB "5034439" using the reject list. I'll keep you posted if we find a solution, and if you come across one, please share it here.
Thanks,
Vignesh