Wifi chip is a rtl8723bs, with the Armbian of balbes150 from https://users.armbian.com/balbes150/arm-64/. So here's the log from the chip:
[74759.888047] RTL8723BS: rtw_set_802_11_connect(wlan0) fw_state = 0x00000008
[74759.934607] RTL8723BS: start auth
[74759.954602] RTL8723BS: auth success, start assoc
[74759.966775] RTL8723BS: rtw_cfg80211_indicate_connect(wlan0) BSS not found !!
[74759.966801] RTL8723BS: assoc success
[74760.063469] RTL8723BS: send eapol packet
[74760.071278] RTL8723BS: send eapol packet
When got no activity going around, it just goes back to normal and I can ssh. Nmap scan shows ssh still active:
Nmap scan report for 192.168.1.X
Host is up (0.012s latency).
Not shown: 99 closed tcp ports (conn-refused)
PORT STATE SERVICE
22/tcp open ssh
Nmap done: 1 IP address (1 host up) scanned in 5.93 seconds
I try upgrade system, different distros, place close to router, open the case. Still helpless.