Hi Johannes,
normally windows10.0-2019-kb5023333-x64-1809.msu would be detected by superseded on the endpoint side and skipped from installation at all like on my server:
but in your case it's most likely shown as "Installed with errors" because of the previous failed attempts.
May you check its status in C:\Program Files\Altiris\Altiris Agent\Agents\PatchMgmtAgent\InstallLog.csv?
Thanks,
Dmitri.