Everything is as it should be. The first subwoofer is the only one which will have the "dot" to the right of the subwoofer name.
The corrected spectrum for the subwoofers will only show on this channel, as it is a target curve which represents all the subwoofers combined.
Conceptually (in Dirac Live ART), target curves are assigned to main channels. When a subwoofer is separated into a different group than the main LFE channel, it will not have a dedicated target curve directly associated to it. It will instead contribute to attain the target of each main channel group it is set to support, including the LFE channel.