I would recommend reviewing the information about the cabling required for your expander card on our RAID controller to Expander Port Connection Information to see the breakdown of the ports.
I would probably contact Intel Customer Support to make sure they review the logs of the RAID controller to make sure that there are no issues in the background with your array.
I am including the table that shows the specifications of the RAID controller. I hope this would cover your question.
This information is taken from our Technical Product Specifications for the controller.