CURRENT: ath0: stuck beacon; resetting (bmiss count 4)

Since a couple of days I get this weird console-and-log-spamming message:

ath0: stuck beacon; resetting (bmiss count 4)

The machine in question is running the most recent CURRENT right now:

FreeBSD 11.0-CURRENT #2 r272471: Fri Oct  3 13:03:58 CEST 2014 amd64

and the box acts as a gateway with WiFi access point via hostapd and this WiFi hardware:

[...]
ath0: <Atheros 9287> mem 0xf7e00000-0xf7e0ffff irq 16 at device 0.0 on pci1
ath0: [HT] enabling HT modes
ath0: [HT] enabling short-GI in 20MHz mode
ath0: [HT] 1 stream STBC receive enabled
ath0: [HT] 1 stream STBC transmit enabled
ath0: [HT] 2 RX streams; 2 TX streams
[...]
ath0: 2GHz radio: 0x0000; 5GHz radio: 0x00c0

What is this and how can I get rid of it?


Regards,
Oliver