I created a scene that specifies some individual bulbs, and it works fine. Later it occurred to me I could simplify things if I created a group for those bulbs, and then include the group in the scene instead. The rule machine allows me to do that (i.e. the list of available devices in the drop-down menu shows both the bulbs and the group I created).
However I found that the capture feature didn't work when the scene is defined using the group. The settings of the bulbs in the group does not update when I execute the capture command. I searched the documentation but found nothing that prohibits the use of groups in a scene. Is it just not documented or perhaps there's something going on with my setup that's not right?
Groups should theoretically work, but a scene is going to set the entire group to whatever setting it captured (e.g., the specific color or color temperature, specific level, etc.). It will not capture individual bulbs within the group separately, so for that you'd need to select them individually for the scene. Another thing to consider is that updating the color or color temperature of a bulb within the group will not change the actual group device status, so either use the group to change those in the first place or make sure the group device shows the states as intended when you capture the scene.
If this doesn't work, there could certainly be some oddities with the Scenes app, but my guess is that there's more likely a problem with the group. Does it work if you manually manipulate the group from its device page? For example, try setting it to specific color temperature or level. The Group itself also has some settings in the app that may help, like Zigbee group broadcasting (or not, but usually it helps) if they are Zigbee bulbs.