dual hard drive kit with Samsung 830 series 256GB drive

I added a Samsung 830 series 256GB drive to a late 2012 mac mini using the ifixit dual drive kit. No issues with the installation or formatting the new drive. However, the drive is very flaky (randomly dismounts during long file copies, gives error messages when trying to repair in Disk Utility, etc) inside the mini versus outside in a bus powered external usb 3 enclosure. Disk Utility will format consistently, it is not consistent in the repair mode where it gives warning messages that the disk cannot be repaired.

I am copying all the files using the external enclosure to confirm that doesn't fail and then move it back into the mini to see if the flakiness is still there.

Anyone else with any experience using Samsung 830 series SSDs in the late 2012 mac mini?