It's not really a bug, per-se, but rather a sequencing thing. You need to create the bridge-vlans, then edit the lan interface to use the new bridge-vlan. This is tricky to do in LuCI because of the way it applies the changes. I think it is possible to get LuCI to queue the changes and apply them in bulk, but I always just directly edit the text files so that I can ensure everything gets applied at the same time.
Meanwhile, glad it is working!
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Thanks! 