This is usually not something to worry about. The Update History page is not a permanent record of every feature update ever installed. After major upgrades, enablement packages, cleanup, or Windows Update database refreshes, older feature update entries may disappear. The more reliable place to confirm the current version is Settings > System > About or by running winver.
Since the system now shows Windows 11 25H2, the upgrade itself appears to have completed successfully. The slow wake from sleep and restart yesterday is probably unrelated, although the restart may have allowed Windows maintenance or cleanup to finish. This should not affect future updates as long as Windows Update continues to scan and install updates normally.