I think they tried to explain the non-instructional dive earlier, at #147:
147. Pursuant to the PADI RRA Membership Standards, the Gull Dive Defendants had a duty to ensure that Linnea was appropriately certified for noninstructional dives – in other words, that she was certified to use a dry suit while other students in the water during her Advanced Open Water course were taking a Dry Suit Diver Specialty Course.
193. Although Linnea was wearing a dry suit in the water, she was not qualified to take part in the dry suit diving portion of the training. Linnea was not a certified or qualified dry suit diver, she had no experience diving in deep water, and she was incapable of assessing risk or making an informed decision to take part in that dive. Despite this, the Gull Dive Defendants made no effort to ensure that Linnea was appropriately certified to participate in this dive, which was a noninstructional dive for her.
I have no idea how it was determined that it was the drysuit diving portion of the training, since they didn't seem to have outlined any skills or done any skills towards it, as you said. There are gaps for sure, but they seem to be trying unsuccessfully to explain it.