How to keep my users off bounced email list?

It seems like when my users have an out of office reply - JotFrom places them on the bounce email list...

Is there anyway to prevent my users from ever being placed on the bounce list?

I would recommend you to set up a custom sender email address using the SMTP method, this way you avoid emails to be added to the bounce list, the following guide will help you with that: https://www.jotform.com/help/244-How-to-Setup-SMTP-for-a-Form 

I hope this helps.