Wireless survey always shows every network as WEP

Hi everyone:

Whenever I do a Wireless Survey from within my Asus RT-N66R running v1.28.0511 MIPSR2Toastman-RT-AC K26AC USB VPN, pretty much every network shows up like this:

infra wep
shortpre
shortslot
802.11n sgi20


A couple of questions. I assume it's a bug that every network displays as using WEP, regardless of what capabilities it has or has enabled? IF so, is there any way to fix this?

What does sgi20 mean?

Thanks