Did you contact Sea Sonic USA over this matter? Please send a PM to me with details.
Please note, it is difficult to make any diagnostic of your power supply based on information of your specs or test results / symptoms. For an accurate diagnostic, our service center will need to test the PSU. Sometimes, rather than long e-mail threads and lots of back and forth, it might be easier just to ask you to send in the PSU and have it swapped out.
As for the new unit, we do change our cases from time to time, but that is only for aesthetics.