We’ve had a lot of users with plugin scanning problems in Dorico and I’ve created an update to the plugin scanner that can be run manually, which may show which plugins are being scanned every time. There is a flag that a plugin can set to say “Always scan me every time”. The reason for this is that some of them do license checks at startup, and there is one dll but many different plugins inside it, and it wants to see which plugins are available (Waveshell is one example of this).
If you download and run the vstscannermaster as described in Ulf’s post then it may show which plugins are causing the problem: