Recently when I build the standalone EXE Unity runs through the entire lighting build again, even though I’m building the player immediately after building lighting in the editor. It seems like it should just use the that lighting build and its lightmaps instead of making me sit through all the steps of a new lighting build. I don’t remember it doing this before and I’m wondering if it’s a checkbox somewhere that I may have inadvertantly checked.
Well, one of two things changed it. I unchecked the “Auto” checkbox and I made triple-extra sure to save the scene before compiling the player. Since I think I’ve reliably used the “Auto” box before, I’m willing to bet that I just forgot to save the scene after the lighting build finished so Unity didn’t see/verify/trust/etc any lightmaps that were already there.
I usually reflexively save the scene, but not saving the scene would explain the inconsistency with having this happen only sometimes.