Today I made the test again and here is the result:
I installed version 4062 or 4104 of cantabile.
I made a new song with two sounds in KONTAKT 6 vst3 for each version.
I played some notes very rapidly.
During this I switched between the states (it doesn’t matter if I switch via GUI or via a binding)
Settings folders for both version (4062 and 4104) are saved.
Songs for both versions are also saved.
I made a recording for each version.
Result: Hanging notes when I use 4104. The hanging notes are muted when I play the same key with the new intrument.
Also the unknown plugins appear again when I update to version 4104 and do no full rescan of the plugin folder.
Hope this is helpful.