The presets are imported, they just aren’t showing. This is due to how they were created and your particular Lightroom settings.
Lightroom Classic #
In Lightroom click on Edit (win)/Adobe Lightroom (mac), then select Preferences. On the Presets tab under Visibility check the box next to “Show Partially Compatible Develop Presets”. Click Okay. Your presets should now display.
Lightroom CC #
In your Preset panel click the three dots in the upper right corner. Then click on “Hide Partially Compatible Presets”. The checkmark next to it should disappear and your presets should now display,.
Lightroom Mobile #
Open the photo you want to edit, open your preset panel. Tap the three dots in upper right and uncheck “Hide partially compatible presets”. Your presets should now display.