This is (no) thanks to a new feature in the Edison email app that allows users to sync messages. However, as some users have reported, for some reason it has synced the messages belonging to other users who also use the app, thus allowing some emails to be read by complete strangers.
According to the developer, it seems that this might have only affected a “small percent” of their users, and they have since rolled back the update to prevent it from spreading further. However, even then we imagine that it might be too late because there’s really no way for someone to “unread” the email message belonging to someone else.
We are urgently working to resolve this technical problem in Edison Mail. Yesterday a software update rolled out to a small percent of our users. We have reverted that now and are reaching out to users who have been impacted as fast as we can.
— Edison (@Edison_apps) May 16, 2020
The developers are also stressing that this is by no means a data breach and that they have not been hacked. They have also since reached out to users affected by this, but like we said, we’re not sure what can be done once an email has been ready. We can only hope that the messages that were accidentally synced to another account did not contain sensitive information.