mquid, thanks for the lat/long. on my iphone, as a quick glance, i see both the main and secondary channel which means that we do have the cartography detail you are refering to on the chart. The question becomes now, why it isnt showing for you.
make sure that on your humminbird that the spot soundings are turned on. on some of the newer software, Humminbird made it a bit more complicated for all features to "automatically" turn on. make sure all are turned on for you. the next question is, and i hate to say this, if you have the absolute latest software, you may need to revert back to the old one. i'm checking with engineering on it right now. the detail is there, so its defintiely on Humminbird side.