Hi all, apologies.. not an expert:

I’m experiencing an odd issue with my BE550 BE9300 router and wanted to check whether this is expected behaviour or a known firmware issue.

Setup:
Router: BE9300
Smart Connect: Disabled
Separate SSIDs created for:
2.4 GHz (WPA2/WPA3 mixed)
5 GHz (WPA2/WPA3 mixed)
6 GHz (WPA3 only – no other option available)
DHCP enabled
Same LAN/subnet for all SSIDs
No guest networks or isolation enabled

Problem:
Devices connected to 2.4 GHz or 5 GHz show “Connected, no Internet”
Devices connected to 6 GHz work normally and have full internet access

If I re-enable Smart Connect, everything immediately works again on all bands

Observations / tests:
Clients on 2.4/5 receive valid IP addresses (not 169.254.x.x)
They can access the router UI but not the internet
Rebooting does not help unless Smart Connect is enabled
Disabling 6 GHz entirely and using only 2.4 + 5 (WPA2/WPA3 mixed) also works

Question: Is this a known limitation or firmware issue when:
SSIDs are split and
6 GHz is WPA3-only while 2.4/5 are WPA2/WPA3 mixed?
Is there a recommended configuration to allow split SSIDs with 6 GHz enabled, or is Smart Connect required for correct routing in this case?

Ps. When smart connect enabled, I just get devices struggling with buffering at random times and I never had that before with my previous router. Now that I split again and disabled 6g.. again seems fine so far.