How come the clock is wrong by exactly one hour after every update?

An exact one-hour difference usually points to time-zone or daylight-saving rules, rather than failed time synchronisation. Windows can synchronise correctly and still display the wrong local time.

Under Settings > Time & language > Date & time, keep Set time automatically enabled, but temporarily turn off Set time zone automatically and manually select the correct zone for your location. Check the daylight-saving option too, if available, then click Sync now.

After the next restart, check whether the selected time zone changed or whether only the displayed time changed. If the zone keeps reverting, location detection, an organisation policy or a manufacturer utility may be resetting it.

Don’t manually subtract or add an hour to compensate. If the correct zone and daylight-saving settings remain unchanged but the error returns, record the Windows build and update KB number so it can be checked against a specific update issue.