We’ve tracked down the year 1899/1900 bug. It should only affect you if you have “Prefer local metadata” enabled on the library. Disabling this option in the library settings and refreshing the affected media should fix it.
99% of the time you should not need this setting enabled. It’s only really required for power users who manually curate their own metadata tags in mp4 files.
We’re looking at a fix for those users who rely on this setting.
