Hi,
I've noticed that Native access doesn't install VST3 plug-in on the first install of an update, I always have to reinstall all it, for the updated VST3 to be installed sometimes it takes 3-4 reinstall for it to happen.
Without knowing which OS you use etc. it's impossible to say anything.
I'm using Windows 10 and Native Acces 3.4.0 but I've noticed this problem since Native Access 3.3.0
Do you need more information ?