And there wasn’t really another forum that seemed to be applicable at the time, and it is an OS question. This would be a great indication that someone has seen this issue elsewhere.
Add to the teeny indication that the R11e-5HnD is a Mikrotik radio, this is a support forum. I’m investigating why I’m not seeing the radio correctly. There is scant support documentation out there.
“Any reasons not use X86 RouterOS?” might have been a better retort.
Mikrotik uses their own drivers in RouterOS, so it’s 3x3 there. I think they sell it as an add-on for their routers…as indicated by they don’t offer drivers for them. If they didn’t just work on a Routerboard device, it be a bug.
So other than looking at the ath9k source OpenWRT is using to see how it determines the number of antennas ports, not a lot can be done.