…other objects shows broken faces or nothing but the selection boundary.
Can you attach a screenshot? This is likely not a volume problem.
For volume disappearing, I find that re-assigning the SVT asset helps. This feature is really buggy at the moment. Lemme know if this fix it or not.
Also, see if you have “isPlaying” enabled on my blueprint. That boolean value is going to disable volume rendering in editor viewport, but shows in PIE or game.