A significant DSA roaming fix went into 21.02 branch yesterday for the MV88 switches in all mvebu routers (along with the new wireguard). It's in the new snapshots and will presumably be in this next build here. I wonder if that'll help some of these less common network setups people have here using external switches. Some really nice polishing is happening on 21.02 branch and it's starting to look like 21.02 will be a very solid release once its done.