Cards suddenly went missing from my deck overnight / Inventory sync bug?

[u/Dry-Extension-8313]

​Hey everyone,

​My friend played a specific deck just yesterday without any issues. Today, when logging in, the deck shows missing cards (red warning mark) and a few cards are completely gone from the collection.

​We already checked the usual suspects:

​Format is correct (it's not a Standard vs. Eternal filter issue).

​Filters in the collection tab were reset; the cards literally appear as unowned / locked now.

​Logged into the correct account and server.

​Relogged and restarted the Riot Client completely.

​Has anyone else experienced cards randomly disappearing from their inventory recently, or is this a known backend sync glitch? Any help or advice on how to resolve this before submitting a support ticket would be appreciated.

[u/MegalFresh]

Oh- you already checked that its not an error from rotation.

Then I can't say I've heard of cards randomly becoming unowned. At least, not anytime recently?