RBG LED randomly turns off

Hi guys.
genuine 3DR pixhawk
Running 3.4 rc6

I’ve got an issue. During some flights or power cycles, the RGB LED and the exteral i2c RGB LED are both extinguished until the next power cycle. They behave totally normal for a few minutes. you can see the calibration lights, then the green or blue blink depending on mode while disarmed (solid if armed). At some point on the ground or in the air, they go off. I have not seen this in earlier firmwares. Doesn’t seem to matter if it gets armed or not. No other issues seem to be coupled. It still flies fine and telemetry looks normal.

I did a search and came up pretty empty on similar issues.

Correction. The symptom I’m observing is only on the external LED. My flight controller is buried, I forgot that when an external light is used, the main board RGB is not used. When I observed the external light off, I peaked in and saw the main light also out (it should be). I can try another external LED, but I have learned of one other 3.4 user that has seen an odd lights out event.

I have observed similar issues with Pixfalcon in a quad on the external LED/USB, again, due to the Pixfalcon being buried in the quad.

I just thought this was due to the LED/USB being an eBay special out of China.

And it does appear to be totally random.

I have seen same with BG Pixhawk and cheap $6 led/usb …

I did try another external LED module. It behaved the same. Interestingly, behavior is normal on the bench using USB power. Using the DC/DC onboard the multirotor (into power 6pin df13), I get the poor results.

Does anyone know where I can get more info on this hardware, what is that LED driver chip? It doesn’t seem to be open hardware. No easily found schematic.