Campaign Email Send Event Triggers but no Email Sent

Your software
My Mautic version is: 3.3.4
My PHP version is: 7.3.11
My Database type and version is: 10.5.9-MariaDB

Your problem
Many users in a campaign properly trigger the email send event, but never get an email sent (it’s not just that it doesn’t get delivered it’s never even queued up and there is no record in the email_stats table)

We have a campaign that looks like this

Many users seem to have the conditions trigger correctly and get the event for ‘Win Back Trial First Email’ scheduled which looks like this

However only a small fraction of these users actually get the email, the majority of contacts stop there and ‘freeze’ because they don’t go to the next event in the campaign. We can modify the campaign so that events aren’t dependent on the email before, but why is the first email being trigger but not actually scheduled for the majority of users? I realize it’s a marketing email as well, but none of these users have been sent this email before so there is no reason for that to be a reason for it not being sent.

Stuck User

Expected Results

There are no errors in the logs related to these or the campaign_lead_event_failed_log table.

Steps to fix problem:
I saw a few posts about Add --batch-limit=10 flag to your mautic:campaigns:trigger CRON job so I’ve tried that now, but they all seem to be related to older versions of Mautic and not 3.3.4

Adding --batch-limit=10 flag to mautic:campaigns:trigger job seems to have fixed the issue (at least for the last 3 days). Is this not something we can trigger an error for if it is failing / running out of resources so it doesn’t process every job in the batch? This has been causing issue for awhile without us knowing because no errors are thrown.