Cron processing queue every other run?


I have my delivery server setup to limit mail to 300 per minute. So far it is working great. I was doing some math, and it seems that it is taking double the time to complete the send. I know I can increase the number, but I noticed that the send-campaigns cron does a send and it works for 20-25 seconds, then the next one works and only lasts 1-2 seconds. This means that every other minute, it will send. Is this a known issue or did I misconfigure something? I checked the Linux and resource usage is very low.

Please keep in mind that setting a certain number per minute doesn't actually means the app can send that much, although, in most cases, MailWizz will since it is configured for speed, but don't take it for granted, lots of things during the sending process can make it take much more time to reach that number.
This means that every other minute, it will send
It means each minute will run and look for new subscribers to send. However, things are much more complex than that, because, for example, if you have already started a running batch of campaigns, although the cron will run next minute, it will do nothing, since sending already is running, otherwise, you'd overload the server to the point it would be unusable.
MailWizz does a lot of work to make sure it keep a high throughput if your settings dictates this, but also not kill your server.

id I misconfigure something?
It seems you did not, from what you described, this is just regular behavior.