We already went through this whole "speculation" scenario...
There is nothing wrong with my install.
I had to prove that... more than once.
Only the slave amp had went out, not both.
The repair center fried the master amp, i didnt, they just wanted it to make sure it wasnt damaged. Rca connector broke off inside the slave amp while they had em strapped and killed em both. I couldnt have done that... Why? because the slave amp never worked for me in the first place so i had no play time with messin with the rcas to begin with.
Before that, a toroid shorted out... that's impossible for me to do that unless it suffered from massive vibrations but again, i never had a chance to install it so again, not my fault.
I've been over this plenty of times. It was an odd scenario but Audioque has 100% took care of me and this problem so it's a past story now.
It was also metered at 5.39 ohms, not 4, voltage lower than 14.4, so far below 4 ohms at 14.4v. The sine wave wasnt even at full amplitude on the o-scope when did that quick test anyway, it was close but not at full non-clipped potential, it probably had like half a click gain wise before it would max out the wave before clipping so close enough.
IT was sent in the first time due to an unknown signal issue... A signal was not passing through the amps when they were strapped and ended up frying the slave amp.... but when just the master amp was connected, it worked fine...
Hence... i believe the rca connector issue was at fault at that time, just not completely broken off yet.
But again ,the repair center doesnt know the root cause, it's history now, they are coming back next week. There never was a ground issue, both amps read same voltage at the amp's terminals... i just got 2 amps at the wrong time.