Hello,
There are indeed limitations with Wake on LAN functionality.
Currently interface name is hardcoded as br-lan, which means that once a user creates additional LANs or deletes default LAN and uses a different name, the backend service will not find the interface and Wake on LAN functionality won't work.
The developers are aware of this, the issue is planned to be improved in the future, however, at the moment there are no timeframes, when it can be expected.
Best regards,