Does anybody know how to fix this issue?
No news from you for a while. We’re closing this thread now. If you still need assistance on that topic, please get in touch here: http://bit.ly/NIsupport_KKontrol
it might be that this particular plugin is not licensed or activated on the computer or there is an issue with that installation, usually. *edit grammar*
If not maybe see if you can open those same plugins in something else if you have a second DAW or something like that or just check for updates for the software, I know it sounds simplistic but often times its just an activation issue or sometimes compatibility that stops plugins from being scanned
And if you checked the said plug-in is functional somewhere else, it's also worth checking if this happens in Komplete Kontrol in standalone, I think I recognize Logic here.
Also important if you're on Mac, make sure that Logic and Komplete Kontrol both have full disk access: How to Enable Full Disk Access on macOS