Hi,
This is what I would do if asked to do something to fix your problem. I'd try to restart from scratch with a clear NVM and if problem still present then I'd go with a Forced Altboot (complete Reload of the firmware with no saved parameter.) Reconfigure without using any clone file. Wait and see. If still present, then I'd start replacing parts (Main PWB, Memory, Software Module).
Hope it's help.
K.