Great question, harrythecoolb! Let's see if we can get Light mode back on your headset.
Some users have reported that sometimes Experimental Features can be missing. This can often be fixed by simply turning Experimental Features off, rebooting the device by holding the power button for 30 seconds, then upon rebooting the device, turning Experimental Features back on.
Let us know if this works out, and feel free to ask us for more help anytime!