ZenWiFi BD4 nodes ignore 5GHz channel setting – always stuck on ch 36

[Cico75]

Hi, issue here with ZenWiFi BD4 nodes

I have the same channel sync problem but with the newer ZenWiFi BD4 (WiFi 7) nodes connected to a RT-AX88U Pro (Merlin 3006.102.7) via wired Ethernet backhaul.
Setup:

• Main router: RT-AX88U Pro (Merlin 3006.102.7)
• 2x ZenWiFi BD4 nodes – both wired backhaul (2.5G and 1G)
• BD4 firmware: 3.0.0.6.102_58138

Problem:No matter what 5 GHz channel I set on the main router (Auto or fixed – tried 36, 40, 44, 52, 60), both BD4 nodes always stay on channel 36. The router follows the setting correctly, but the nodes simply ignore it.

• DFS enabled/disabled → no effect
• Full power cycle of all devices → no effect
• Router Optimization button in ASUS app → non-functional
• BD4 nodes have no own web GUI, so no direct access

Result: Router on ch 60, nodes on ch 36 → massive interference and very unstable speeds (fluctuating between 5–470 Mbps).

Workaround: Fixed router to ch 36 to match nodes, but ch 36 is heavily congested here.

Has anyone found a solution for the BD4 specifically? ASUS support ticket has been submitted.
Regards