we are facing some issue with the personalization priority order. Sometimes, it seems that the priority level is not considered when multiple campaigns run on the same page. This behavior seems to be correlated to the mbox3rdpartyid. We are thinking this because every time we pass that value the priority is not considered, while if we do not pass that value the priority is considered.
Thanks for your question! You may find this article on Priority within the Adobe Target Product Documentation helpful. Feel free to reach out here again if you have any follow up questions. Hope this helps!