I just noticed that a known kernel bug is also affecting Manjaro:
When sporting a BCM43602 SoC WiFi & Bluetooth chip, which is present in WiFi cards labelled "Dell Wireless" like in the Dell XPS 9550 and some Apple MacBook Pros, the system freezes hard when there's heavy load on the WiFi.
It seems that it's occuring when connected to WPA2 Networks.
I tried installing
wl-wireless, but this package doesn't support this chip. The only way around this panic seems to be swapping in an alterantive wifi card, unless there's another driver package suppoting this SoC.