Windows 8.1 shipped 11 years ago and was EOL 6 years ago.
So even if it works perfectly in that most people won’t be running it today anyway.
I’m not sure if I can get a video of it but my explanation of the problem should be pretty straight forward: opening and closing two different LSP 1.2.16+lsp-ws.lib fix plugins several times in Ardour 8.6 causes it to need a mouse movement to react to whatever has been clicked.
I’ll see if I can try a nightly Ardour build, though.
Did you try with 1.2.16 + the cherry picked ws.lib fix or did you use the devel branches all the way down?
I suppose my cherry picking of just the registration fix could be missing out on something else in either the ws.lib or in a recent fix in some of the other modules.