All,
The issue seems to be fixed for me now...
After reading the last post from MarcSThe1st, I decided to play around with my power supplies. My Pineapple was powered by a 9V @ 1.5A power supply. I'm not sure that's the supply it came with. I changed this to 12.6V @ 1A and lo and now wlan1 is back and working.
Just for the fun of it, changed back to the 9V power supply and wlan1 is still there...