Hi.
I am using both pci-wifi cards (5GHz and 2.4 GHz) and noticed that only the PCI1 LED was lit and indicating activity, the PCI2 LED is off. This appears to be due to problem with the LED configuration in etc/config/system.
The respective configured devices to trigger LEDs 1 to 3 are named wlan1 to wlan3, but the two active wifi interfaces are named wlan0 and wlan1. After changing this in the config file and rebooting the system, the LEDs are now working as intended.