I have this problem with Flint 3 (I am actually on 4.9.0 stable):
I have MLO configured to use 2+5+6Ghz and if I connect with a Wifi7 dual band device the connection is succesfully established (in this particular case I am talking about a Xiaomi 14T Pro which is a wifi7 device, supports 6Ghz but it's dual band).
If I am near the router, the phone correctly uses 2.4+6Ghz:
ue May 26 11:17:38 2026 kern.err kernel: [245203.189142] wlan: [0:I:ANY] [INACT] vap-4(wlan22):ieee80211_recv_asreq: Max BSS Idle enabled client
Tue May 26 11:17:38 2026 kern.err kernel: [245203.200816] wlan: [0:I:ANY] [INACT] vap-1(wlan02):ieee80211_recv_asreq: Max BSS Idle enabled client
Tue May 26 11:17:38 2026 kern.err kernel: [245203.214664] wlan: [0:I:ANY] [INACT] vap-1(wlan02):ieee80211_setup_assocresp: Setting BSS Idle Time to 291 for Max BSS Idle client
Tue May 26 11:17:38 2026 kern.err kernel: [245203.215027] wlan: [0:I:MLO_MGR] wlan_mlo_peer_create: MLD ID 0 ML Peer XX:5b:8c:e4:8f:XX allocated 00000000fb1e4a92
Tue May 26 11:17:38 2026 kern.err kernel: [245203.252959] wlan: [0:E:MLO_MGR] wlan_mld_get_best_primary_umac_w_rssi: Skip Radio for Primary MLO umac
Tue May 26 11:17:38 2026 kern.err kernel: [245203.252998] wlan: [0:I:MLO_MGR] mlo_peer_allocate_primary_umac: MLD ID 0 ML Peer XX:5b:8c:e4:8f:XX avg RSSI -44 primary umac soc 1
Tue May 26 11:17:38 2026 kern.err kernel: [245203.261234] wlan: [10713:I:MLO_MGR] wlan_cfg80211_prim_netdev_notification: link id: 0, ifindex: 99, macaddr:XX:5b:8c:e4:8f:XX
Tue May 26 11:17:38 2026 kern.err kernel: [245203.273485] wlan: [10713:I:MLO_MGR] wlan_cfg80211_prim_netdev_notification: Vendor event Created for peer mac address: XX:5b:8c:e4:8f:XX mld address: XX:5b:8c:e4:8f:XX Peer Link ID:2, Primary peer ifindex: 101,MLD ifindex:98
Tue May 26 11:17:38 2026 kern.err kernel: [245203.285027] wlan: [10713:I:ANY] [INACT] vap-4(wlan22):ieee80211_setup_assocresp: Setting BSS Idle Time to 291 for Max BSS Idle client
Tue May 26 11:17:38 2026 daemon.info hostapd: wlan22: STA XX:5b:8c:e4:8f:XX IEEE 802.11: associated (aid 1)
Tue May 26 11:17:38 2026 kern.err kernel: [245203.309090] wlan: [10713:I:ANY] wlan_cfg80211_change_station: Ignore set station for ap vlan wlan22
Tue May 26 11:17:38 2026 kern.err kernel: [245203.316810] wlan: [10713:I:ANY] wlan_cfg80211_change_station: Ignore set station for ap vlan wlan02
Tue May 26 11:17:38 2026 daemon.info hostapd: wlan22: STA XX:5b:8c:e4:8f:XX WPA: sending 1/4 msg of 4-Way Handshake
Tue May 26 11:17:38 2026 daemon.info hostapd: wlan22: STA XX:5b:8c:e4:8f:XX WPA: received EAPOL-Key frame (2/4 Pairwise)
Tue May 26 11:17:38 2026 daemon.info hostapd: wlan22: STA XX:5b:8c:e4:8f:XX WPA: sending 3/4 msg of 4-Way Handshake
Tue May 26 11:17:38 2026 daemon.info hostapd: wlan22: STA XX:5b:8c:e4:8f:XX WPA: received EAPOL-Key frame (4/4 Pairwise)
Tue May 26 11:17:38 2026 daemon.info hostapd: wlan22: STA XX:5b:8c:e4:8f:XX RADIUS: starting accounting session 5A01CFCCB215F1FB
Tue May 26 11:17:38 2026 daemon.info hostapd: wlan22: STA XX:5b:8c:e4:8f:XX WPA: pairwise key handshake completed (RSN)
Tue May 26 11:17:39 2026 daemon.info dnsmasq-dhcp[1]: DHCPREQUEST(br-lan) 192.168.8.175 XX:5b:8c:e4:8f:XX
Tue May 26 11:17:39 2026 daemon.info dnsmasq-dhcp[1]: DHCPACK(br-lan) 192.168.8.175 XX:5b:8c:e4:8f:XX Xiaomi-14T-Pro
Tue May 26 11:17:41 2026 user.notice qsdk-wifi: vap stable confirmed after 3 rounds: ifname=wlan2
Tue May 26 11:17:41 2026 user.notice qsdk-wifi: vap stable confirmed after 3 rounds: ifname=wlan22
If I move from the router, as the 6Ghz signal becomes weak the phone tries to dinamically change the 6Ghz link with the 5Ghz one (as per Wifi7 standard) but what happens is a complete MLO teardown with disconnection and reconnection:
Tue May 26 11:20:54 2026 kern.err kernel: [245398.755199] wlan: [0:E:MLO_MGR] mlme_recv_auth_ap: ML Peer exists with this MAC XX:5b:8c:e4:8f:XX send auth req to hapd
Tue May 26 11:20:54 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX IEEE 802.11: authenticated
Tue May 26 11:20:54 2026 kern.err kernel: [245398.762257] wlan: [0:I:ANY] [INACT] vap-1(wlan12):ieee80211_recv_asreq: Max BSS Idle enabled client
Tue May 26 11:20:54 2026 kern.err kernel: [245398.766004] wlan: [10713:I:ANY] [INACT] vap-1(wlan12):ieee80211_setup_assocresp: Setting BSS Idle Time to 291 for Max BSS Idle client
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX IEEE 802.11: authenticated
Tue May 26 11:20:55 2026 kern.err kernel: [245399.879949] wlan: [0:I:ANY] [INACT] vap-1(wlan12):ieee80211_recv_asreq: Max BSS Idle enabled client
Tue May 26 11:20:55 2026 kern.err kernel: [245399.893120] wlan: [0:I:ANY] [INACT] vap-1(wlan02):ieee80211_recv_asreq: Max BSS Idle enabled client
Tue May 26 11:20:55 2026 kern.err kernel: [245399.907173] wlan: [0:I:ANY] [INACT] vap-1(wlan02):ieee80211_setup_assocresp: Setting BSS Idle Time to 291 for Max BSS Idle client
Tue May 26 11:20:55 2026 kern.err kernel: [245399.907554] wlan: [0:I:MLO_MGR] wlan_mlo_peer_create: MLD ID 0 ML Peer XX:5b:8c:e4:8f:XX allocated 000000002de29087
Tue May 26 11:20:55 2026 kern.err kernel: [245399.919126] wlan: [0:E:MLO_MGR] wlan_mld_get_best_primary_umac_w_rssi: Skip Radio for Primary MLO umac
Tue May 26 11:20:55 2026 kern.err kernel: [245399.928513] wlan: [0:I:MLO_MGR] mlo_peer_allocate_primary_umac: MLD ID 0 ML Peer XX:5b:8c:e4:8f:XX avg RSSI -66 primary umac soc 1
Tue May 26 11:20:55 2026 kern.err kernel: [245399.937645] wlan: [10713:I:MLO_MGR] wlan_cfg80211_prim_netdev_notification: link id: 0, ifindex: 99, macaddr:XX:5b:8c:e4:8f:XX
Tue May 26 11:20:55 2026 kern.err kernel: [245399.949791] wlan: [10713:I:MLO_MGR] wlan_cfg80211_prim_netdev_notification: Vendor event Created for peer mac address: XX:5b:8c:e4:8f:XX mld address: XX:5b:8c:e4:8f:XX Peer Link ID:1, Primary peer ifindex: 100,MLD ifindex:98
Tue May 26 11:20:55 2026 kern.err kernel: [245399.961634] wlan: [10713:I:ANY] [INACT] vap-1(wlan12):ieee80211_setup_assocresp: Setting BSS Idle Time to 291 for Max BSS Idle client
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX IEEE 802.11: associated (aid 1)
Tue May 26 11:20:55 2026 kern.err kernel: [245399.985814] wlan: [10713:I:ANY] wlan_cfg80211_change_station: Ignore set station for ap vlan wlan12
Tue May 26 11:20:55 2026 kern.err kernel: [245399.993341] wlan: [10713:I:ANY] wlan_cfg80211_change_station: Ignore set station for ap vlan wlan02
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX WPA: sending 1/4 msg of 4-Way Handshake
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX WPA: received EAPOL-Key frame (2/4 Pairwise)
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX WPA: sending 3/4 msg of 4-Way Handshake
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX WPA: received EAPOL-Key frame (4/4 Pairwise)
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX RADIUS: starting accounting session A868940431437EF0
Tue May 26 11:20:55 2026 daemon.info hostapd: wlan12: STA XX:5b:8c:e4:8f:XX WPA: pairwise
Is the ML Peer exists the problem here? Seems that Flint3 can't manage a band change request form an already MLO connected dual band device and it just kills and re-create the MLO connection from scratch...
I don't think it's a phone's problem as my nephew's laptop (also a wifi7 dual band device) had the same behaviour and in the logs I found the same ML Peer exists when it disconnects/reconnects.
Final note: I have the bss_transition=0 on all the six interfaces because of the infamous occasional EAPOL LOOP bug wich basically makes the router unusable and I also have Hardware acceleration OFF because it always gave me problems with MLO.
Apart from the frequent disconnection/connection problem with dual band devices, MLO is now working great with the bss transition workaround.