When using hostapd on multiple network devices at the same time (hostapd /etc/wlan0.conf /etc/wlan1.conf ...) it seems that it always logs on the last configured interface. This gives incorrect log messages like: Feb 16 17:12:51 gw hostapd: wlan2: STA 9c:fb:da:a6:2b:14 IEEE 802.11: disassociated due to inactivity even if the message is really about wlan0
Just checked: hostapd <= v2.5 logs some strange / duplicate messages about association on both interfaces (with subsequent disassociation on the wrong one); however, these messages are gone after wpa_supplicant v2.6 update (base r336203).