I’ve made an update to prevent the error caused by is_bounce?.
There is a site setting for tracking mail logs:
SiteSetting.log_mail_processing_failures
Log all email processing failures to /logs
If this is enabled, the blank email error will still appear in the mail logs but won’t cause the job to fail like it does currently. I’ve added the commit details here for reference:
https://github.com/discourse/discourse/commit/1de8361d2e4309df097d33381d885df9cbbd3b93