@anselm.haselhoff not sure if it will help you anymore but I resolved the situation by deleting some of the preferences files in my home directory. You can drop this in a file called something.command or paste it into the terminal:
mv ~/Library/Application\ Support/Neural\ DSP/Darkglass\ Ultra/Darkglass\ Ultra.settings ~/Library/Application\ Support/Neural\ DSP/Darkglass\ Ultra/Darkglass\ Ultra.settings.bak
mv ~/Library/Audio/Presets/Neural\ DSP ~/Library/Audio/Presets/Neural\ DSP.bak
mv ~/Library/Caches/com.juce.locks/juceAppLock_Darkglass\ Ultra\ ~/Library/Caches/com.juce.locks/juceAppLock_Darkglass\ Ultra.bak
mv ~/Library/Preferences/Darkglass\ Ultra.settings ~/Library/Preferences/Darkglass\ Ultra.settings.bak
Make sure Logic is closed / Darkglass plugin is not loaded in any DAW when running the above. It should not delete your old preferences in case you somehow still need them.
After moving these old files out of the way, reset and rescan in Logic.