Duplicate private messages and emails

We have email and PM auto actions that are triggered by cron jobs to run on all users. These have been in place now for many months but after recent CB update (which now included the auto action batch limit feature) the PM's and emails are being sent out twice each time the cron job runs. From looking at the PMs in Plugin Management, the PM is sent to each user once, then after that, it is sent to each user again. The same looks to be happening with the emails. I have noticed that this does not happen when I set a batch limit. I would rather not set a limit if possible.
Auto actions build is 8.0.0+build.2020.04.17.17.38.41.bcf774668
CB version is 2.4.5, cant find the build number

Core CB has not impact on CB Auto Actions and its Internal Users behavior. What version of CB Auto Actions did you update from? The batching functionality wasn't added recently and this behavior was not changed recently. Are you sure you're not just running the URL twice from CRON? That would explain why setting a batch limit fixes your issue since it expects the URL to be ran multiple times.

Have also moved your topic to the Professional support forums as you're a professional subscriber and have access to priority support.

Thanks for your quick reply.
I added a "-t 1" to the CRON jobs and it has seemed to fix the issue. I did recently change my CRON's so I guess accidentally omitted this option.
Having said that, I am getting a 504 Gateway Timeout error on the CRON job when not using the batch feature only. I assume this would be a server issue but if you know where to point me to fix it, that would be great.

You're getting a timeout because you're trying to process your entire user base in a single PHP action. This really only works if you've a low amount of users. The batch feature is designed specifically to help with this and am unsure why you're against using it.

Thanks again for your help.
I thought that might be the case.
I have multiple CRON jobs, each with a different "&do=something" in the url. Different auto actions are conditioned for the different URL's.
For clarification in regards to using the batch feature, if I have say, 800 users and I set the batch to 300, do I need to run each CRON 3 times so that it runs across all users?

For clarification in regards to using the batch feature, if I have say, 800 users and I set the batch to 300, do I need to run each CRON 3 times so that it runs across all users?

Yes, but in a future release you won't need to as a redirect will be put in place and as long as the CRON task uses wget or CURL with follow redirects on you'll only need to run it once.