It is more likely an individual LED diode rather than a driver going bad. The reason this usually happens is one of the colors in a 6 chip diode dies open, meaning it won't pass current. Each side of the fixture is wired in series.
In the video, when half of the diodes go out, those 9 diodes are wired in series and one is bad (intermittently) and if that happens, it behaves like old Christmas lights and takes out the others. Even though there 9 chips per half, each chip has an individual LED for each color. If the other colors work, it is just one of the smaller color LEDs that died and not the entire chip itself.
The driver PCB drives both haves at once. If it was the driver you wouldn't have that color at all. If you notice, the working side gets brighter when the other side goes out. That is because the voltage drop from only half the diodes is less though the driver than with them all on, so it drives the working ones a little harder. This can possibly burn out the working diodes faster since they see a higher voltage.
Out of all of the SixPars I have repaired over the years, I have only replaced one driver PCB. But I have soldered in probably 50 of the "Single LED for SIXPAR" chip you can get from the Elation parts store to repair this exact issue across the 200ish Sixpars the company I work for owns. The trick is finding which exact LED is causing the issue. Its usually only 1.
If you have decent experience soldering you can replace the individual diodes. These are SMD LED diodes, which are more difficult to solder and require a good temperature controlled soldering station and skill, otherwise, you will burn out the diodes with heat.
You can track down which LED it is by using a Digital Meter in diode mode and with the fixture unplugged probing every single leg on each of the DIODEs and seeing which don't light and pass voltage.
OR with the fixture on and the intensity set to 20% or something low, you can try bypassing each color of each LED with a short piece of wire until the side comes on full. The one you are jumping when it works again is the bad one. Make sure the fixture is not on full, because you will give the LEDs in series a higher voltage then they are designed if you have it set to full, and you will blind yourself.
The voltage on the PCB when in operation is about 22v if I remember. Not enough to shock you, but it will let the smoke out if you touch the wrong parts.
The solder-free option is a new LED PCB.