Setting the channel to 149 and above fixed the issue. Channels 52 to 140 are DFS channels, which are commonly used by radar signals. The FCC requires that devices on those channels move to other channels if radar is detected.

Please see usable channels below:

802.11n (40 MHz): 36, 44, 52*, 60*, 100*, 108*, 116*,124*, 132*, 149, 157
​802.11ac (80 MHz): 36, 52*, 100*, 116*, 149

* DFS Channel: Some consumer devices may not support

Please see attached file for EnGenius AP Best Practice Configuration.