LiteBeam 5AC Upgrade to 4.26 Lost WAN Internet Access

When upgrading a Ubiquiti LiteBeam 5AC Gen2 from 3.25.10 to 4.26.1, the device lost access to its WAN interface, and therefore all tunnels. I was able to connect on the LAN interface and restore to 3.25.10 via the backup I saved (thanks for the reminder) and the WAN interface was restored. Upgraded again to 4.26.1 and the same problem. After a LOT of trial, error, and recovery, I noticed the help text under the WAN VLAN setting, specifically, "By default, the WAN uses an untagged VLAN on multi-port devices, and VLAN 1 on single port devices." My home network does expect VLAN 1 for internet access and the LiteBeam is a single port device, so the default should work. From the screenshots I took before and after, both had the WAN VLAN displayed as "untagged". The fix for 4.26.1 was to set the WAN VLAN to "1". As far as I could tell, there is not a way to say "use the default", because blank means "untagged".

• Was there a bug in 3.25.10 displaying the WAN VLAN incorrectly?
• Is this a bug in 4.26.1 not correctly using the default for the LiteBeam?
• Is the documentation incorrect?
• Or is there something else I missed?

Either way, maybe this will help others find this solution.

Dan - AK6DM