Here is some important info I have gathered since posting:
I am a UPC customer (my ISP) and use their ConnectBox Modem-Router combo. Apparently this issue is caused by a specific firmware version on this device: CH7465LG-NCIP-6.12.18.25-2p3-NOSH.
There are reports that the latest version, CH7465LG-NCIP-6.12.18.25-2p4-NOSH, fixes this issue. But it has not yet been deployed in all markets.
I have spoken to both LG and my ISP, and they both acknowledged this issue being a result of the firmware. With that said, as previously mentioned, no other devices have an issue with 5ghz and the 2p3 firmware version...so I am inclined to think that this still boils down to a crappy/cheap LG wifi driver