Physics asset collision box colors?

I have a pair of animated fans that have physics assets assigned to the moving blades. I turned on ‘show collision’ in the view port and I can see the collision box outlines. But what has me confused is that one the fans show the physics collision box outlines in a lime green color while the other one shows the collision box outline in black or dark grey. I’m assuming I have a setting that’s different between them, but I can’t figure out which one it is. Could someone offer some guidance what the different outline colors mean for the physics assets?

I have the same question, there is absolutely no documentation about this and I suspect this is a key to my problem with the vehicle flying everywhere without even hitting a collider (while driving on a terrain)