x15 R2, 100W USB Type-C PD, keyboard RGB issues

Recently purchased an Alienware x15 R2 (12700H, 32G, 3080Ti, 1T) with the latest BIOS 1.4.1. 

I use the 240W AC power adaptor at home with gaming needs, no problem at all, works like a charm. 

However, since I only do light workloads when I'm at work, I figured I'd use a 100W USB Type-C PD for power so I could carry only the laptop itself going back and forth to work. 

Whenever I boot the laptop while the USB PD power is plugged in, the keyboard and all RGB lights just do not work. They work fine if I boot with the battery and plug in the USB PD cable afterward. 

First I figured it must have been the issue with the USB PD adaptor or the cable's issue so I changed out both but still the same. Then I tried Dell's own WD19TB dock, which comes with 130W PD, but still the same issue. 

I called Alienware's support but nothing helpful was provided nor have they solved the issue. 

I suspect it is the motherboard or BIOS issue and wondering if anyone else has experienced the same problem.