mysqldump: Couldn't execute 'show events': Cannot proceed because system tables used by Event Scheduler were found damaged at server start (1577)

Backup refuses to run on the command line. Error is the summary
mysqldump --user=myuser --password=mypassword --host=127.0.0.1 --default-character-set=utf8 --single-transaction=TRUE --routines --events "mydb" > mydb.sql

Permissions are correct, this is from a batch job that runs nightly. Has worked in the past. Both the source backup db and the destination test db are having this issue.