My windows date is changing to August 3209

Try to sync time with online server, see if it helps.

If that doesn't helps, upgrade to a newer build or downgrade to previous build.

If issue still persists, drop a feedback to Feedback hub.

Also refer this thread for more ideas: https://techcommunity.microsoft.com/t5/windows-insider-program/my-windows-date-is-changing-to-august-3209-somewhat-often/m-p/2192051