In regards to when you say that you “compile the lighting and then duplicate and move some geo around WHILE the lighting is compiling…” This is not good practice and hence would not be recommended to fix the hot key issue.
When you build lighting, it creates a physical texture where shadows are rendered for static items in the scene. So if you move a box while light is building there could be a shadow rendered for where the box used to be. In short, you only need to rebuild lighting when your done moving things around in a level.
As far as working on a fix for hot keys, there is so much work going on with the engine, anything that only occurs under very specific circumstances is not going to be given a high priority. That said, if you can establish consistent repro steps, on the other hand, it is very likely the bug will be addressed right away.