Light sources don't load on reverting an image until you /reload
With the lighting update out, I went into the adventure module I'm running and added light sources to my maps. Then I exported the module and switched over to my campaign that uses it.
The light sources did not appear. This makes sense as the maps have had changes during the campaign during play (doors opened/closed, blood splatters put down, etc). I figured if I reverted the maps, the light sources would appear. Reverting did cause the light layer to appear, but the actual light sources themselves did not appear.
I closed and reopened the FG and then they were there. With some further testing, I determined that /reload makes them appear too.
TLDR: If you revert a map to pick up the light sources on it, the light layer will appear, but the actual light sources themselves won't until you do a /reload.
Mainly posted this so people know there's a quick workaround.