I'm so sorry to hear that you lost your work due to this bug. I'm Melinda, an engineer working on the the brands and libraries team. I would like to try to understand what happened so we can address the bug. Could you please provide me with more information?
What is your Adobe email ID? Providing this will give me the ability to look in our logs to see if any errors were reported.
Are you able to recall and share the exact actions you were performing that led to the red window popping up?