I sent an email to Arturia support.
As a solution they suggested this procedure:
"Delete a specific temp file called "
db.db3".
MAC: /Library/Arturia/Presets
WIN: C:\ProgramData\Arturia\Presets
If you have not enabled the display of hidden folders please go to your file explorer -> display -> check "show hidden folders"
Alternatively, you should be also able to directly copy/paste the path indicated above in your Windows File browser address bar.
Once this file is deleted, the preset list will be updated on software opening."
My comments:
Indeed the loading time of both standalone and plug-in dramatically changed to very fast.
Please update to latest version and use vst3 if you can.
I think that's a solution !!!