It will probably never be fixed. The baked lighting path has become progressively more broken with every release and seemingly no effort at all has gone into improving the situation.
The way things are going I’d be willing to guess that the next time we hear about it, it will probably be an announcement that they’re deprecating it and it will be removed in UE6.
For what it is worth though, it should work in the community fork of GPULM: Epic's GPUlightmass - #917 by yujiang.wang