Please download the Halion Sonic SE Installer and confirm this strange bug...
https://www.steinberg.net/en/landing_pages/halion_sonic_se_3/halion_sonic_se_free.html
Steps.....
1) Make an instance in VE PRO but do not connect to Cubase 9.5 or 10 on a PC.
2) Load 16 instances of HALION SONIC SE
3) Load VE PRO inside of Cubase and connect decoupled.
Results.... On first attempt to connect it can take around 30 seconds to connect. Once it connects the first time you can disconnect in less than 2 seconds and you can then re-connect as many times as you want but now it re-connects in less than 2 seconds.
Problem...the first time it tries to connect it takes a very very long time.