Board Thread:Game Discussion/@comment-24705123-20131114181932/@comment-11490363-20131114182653

FB page has a post about it:

Attention TRANSFORMERS: Legends players:

We're aware that yesterday's update inadvertently caused your upgraded and trans-scanned cards to be reverted to Level 1.

The game team is working hard on fixing this issue and restoring your Transformers cards to their former glory. In order to do this, they've taken the game offline.

Thank you for your continued patience while we work out the bugs and prepare for the next episode.