Keybase is notifying Android users of a bug in its mobile app that might have unintentionally included the users’ private key into the automatic backups created by the Android OS and uploaded on Google’s servers. The issue appears to affect only “early adopters”” of the Keybase Android app. The company says it has fixed the bug and has sent notification emails to users it believes are affected by this issue. Users who back up their Android device through Google Play and users who reused passwords from other accounts or used a weak passphrase are affected.”
Source: https://www.bleepingcomputer.com/news/security/keybase-bug-might-have-backed-up-your-private-encryption-key-on-googles-servers/