Channel Width Auto vs 20/40 on Balance One.. ("auto" breaks things)

I am using a specialized wifi device that supports 802.11n / 2.4Ghz WPA2 and I connect them as clients to a Peplink Balance One router as part of a larger networking package.

The first few of these builds went okay but lately I have been having trouble getting them connected.

The first problem was that the client would connect to wifi and work for a few seconds and then lose network connectivity (unable to Ping the device). I was using 8.1.0b4943 at the time. After two days struggling with settings I upgraded to beta 8.1.1b02-5015 and it solved the problem. I since upgraded to 8.1.1b5040 and it is still okay.

Then yesterday I ran into a similar problem on my latest build (all the same components, same configuration, etc. Running a Balance One with 8.1.1b5040 I created the wifi network and the client device would NOT connect to the wifi network. And produced an error about inability to connect to an AP in SoftAP mode.

I downgraded the firmware of the Balance One to 8.1.0b4943, and Upgraded it again, no change with either version. I tried different versions of WPA, and contacted the client device vendor. Again, after a whole day of messing with this I changed the 2.4Ghz Channel width from “Auto” to “20/40Mhz” and it solved the issue…

So… Is this a bug? On an 802.11n radio, how is Auto different from 20/40?