Would you mind describing your setup/config? Is it just the apu2 plus a ubiquiti AP? Which AP?
from pcengines, I got:
https://www.pcengines.ch/apu2c4.htm https://www.pcengines.ch/case1d2redu.htm https://www.pcengines.ch/msata16f.htm https://www.pcengines.ch/ac12vus2.htm
put that together and installed pfSense per their instructions:
http://pcengines.ch/howto.htm#OS_installation
You could get their wifi modules:
https://www.pcengines.ch/wle200nx.htm https://www.pcengines.ch/wle600vx.htm
but I advise against it if you want to run pfSense, since driver support on pfSense for these might be sketchy/difficult to get working. Linux might be a better choice for a router OS if you're going to get those modules. My personal recommendation is to avoid getting wifi onboard the apu2 and stick with this instead:
https://www.ubnt.com/airmax/nanostationm/
or if you want 802.11ac:
https://www.ubnt.com/airmax/nanostation-ac/
and just take up one of the three ports available on the apu2 permanently for your Nanostation.
Set this up, and you'll be happy for years. I consider it the ultimate DIY home router setup and I've experimented with many. This one takes the cake. The only thing I wish for is an extra RJ-45 port on the pcengines APU2 for some of the devices that are close by it (e.g. a mac mini I use as HTPC), but since everything or nearly everything has wifi nowadays, you don't get to notice this much. Worst case, if you need extra ports, hit amazon and type only "pfsense" in the box - there's a vendor called ProtectLi (https://protectli.com/) which sells 4 and 6 port boxes similar to the APU2, but with Intel instead of AMD (I'm kind of partial to AMD plus PCEngines is run by Americans/Swiss :). Those will work just as well though you're looking at spending more $$$. If that's no objective, then just get the 4 or 6 port ProtectLi.
Reply here let me know how it works out once you've got it setup the way you want.