There was an update to the orchestrator this week that had an unfortunate side-effect. If you updated your orchestrations' notifications it would delete the orchestration's tasks.
Thankfully, the orchestrations are versioned, so if this happened to you, we will restore the tasks from the last version.
If you have any concerns about this please contact us at support@keboola.com.
For what it's worth, updating notifications will no longer delete orchestration tasks, please accept our humble apologies if you were affected.