I replaced the fuse panel on the top of the battery. Appears to fix problem but I will see. All connections were tight but if I moved the panel slightly power would return. If this doesn't fix it, i will have the positive wire harness replaced.
I have the same problem on 2014 Sierra. Last year dealership, replaced ground cable. Issue started again 2 weeks ago. No consistency on what initiates the error. Sometimes the auto start does it, turning key ignition does it and sometimes battery appears dead.