Brief current spike and all 4 motor studder during flight

I’m running a Quad with Afro Opto ESC’s, 8000 Mah and Sunnky Sky 4108, 3DR Apm 2.6
After flying for a while, and while in loiter mode, all four motors briefly stopped and then started again. It was for a split second that they turned off and then as it started to fall, they cut back on again. At first I thought it was just a control glitch, but after looking at the onboard video, where I can see the rotors and the running lights I noticed the running lights cut out at the exact same time as the motors. They also came back at the exact time the motors did. The copter did not crash. I’m uploading the log, and you can see at the 29 min point there are two current spikes. A slight voltage drop. Vcc seems stable.


I’m guessing it might be a short, but where?