posted about this a few weeks ago. the presets in lightroom cc are a mess since updating to high sierra macos (the actual folder is just fine...the presets show up randomly in lr).
This is a known bug due to a change in the High Sierra OS. It's a work in progress for both Apple and Adobe. There's a partial fix for the issue in Lightroom Classic, but I'm not sure it made it into LR CC yet.
thanks so much!