I have several scenes that involve Lifx lights. There are two in my system, one is the strips and one is the bulb.
Both work fine when activated directly. However, when activated as part of a scene they do not activate at all, even when the scene is activated manually.
Do you have "color pre-staging" enabled for your lifx devices? If so, you'll need to enable the "explicit on" setting in your scene. That's the most likely scenario I can think of. If that doesn't match your case or solve your problem, some screenshots of device settings, scene settings, and logs when you try to activate the scene, would help