This is still a major issue for some people. It seems the issue is project specific. Although, whenever I open the project on a brand new computer, I can typically work in it perfectly fine until I close and reopen again. Then all the actors are broken. Not only that, but if I switch to a known working project after, it also breaks (doesnt seem to stay broken though if you close UEFN and reopen directly). I have the same issues as described above. Actors broken, 95% of devices missing in content browser, devices already placed in the game world are invisible (can still be found in outliner, highlighted, and details accessed etc).