Unstable WiFi - TP-LINK WDR4900 v1.0

[Carves]

I found that the WiFi connection is unstable, it disable it self.
I'm currently running the latest version OpenWrt 21.02.0 r16279-5cc0535800 on my TP-LINK WDR4900.

Log file as shown

Mon Nov  1 16:46:36 2021 daemon.notice hostapd: Remove interface 'wlan0'
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan0: interface state ENABLED->DISABLED
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan0: AP-DISABLED
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan0: CTRL-EVENT-TERMINATING
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: nl80211: deinit ifname=wlan0 disabled_11b_rates=0
Mon Nov  1 16:46:36 2021 kern.info kernel: [241207.212492] device wlan0 left promiscuous mode
Mon Nov  1 16:46:36 2021 kern.info kernel: [241207.217181] br-lan: port 2(wlan0) entered disabled state
Mon Nov  1 16:46:36 2021 daemon.notice netifd: Network device 'wlan0' link is down
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: Remove interface 'wlan1'
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan1: interface state ENABLED->DISABLED
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan1: AP-STA-DISCONNECTED c0:bd:d1:77:c4:10
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan1: AP-STA-DISCONNECTED a8:7c:01:cc:31:c3
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan1: AP-DISABLED
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: wlan1: CTRL-EVENT-TERMINATING
Mon Nov  1 16:46:36 2021 daemon.notice hostapd: nl80211: deinit ifname=wlan1 disabled_11b_rates=0
Mon Nov  1 16:46:36 2021 kern.info kernel: [241207.252375] device wlan1 left promiscuous mode
Mon Nov  1 16:46:36 2021 kern.info kernel: [241207.257032] br-lan: port 3(wlan1) entered disabled state
Mon Nov  1 16:46:36 2021 daemon.notice netifd: Network device 'wlan1' link is down

Any solution for this ?
Thanks

[Carves]

So I solved this eventually.
The problem was that I replaced the stock antenna with the antenna from TL-WR941HP unit which has 3× 9 dBi Antennas.

And since I replaced it back with the stock antenna, the WiFi is back to normal.
Its a shame because I was able to extend the signal, but the unit somehow cannot maintain stability.