mmmm..I think you are right.
I try to reproduce your same step and sometime happen here too.
I have update the vstHost 1.47 double precision32/64bit and happen much less.
IF you give some time for the changes, the vsthost work a little bit better, seem like that the CPU when change VST go in overload for some ms.
When vst host hang and you lost signal, touch on bottom the Wine TAB, for select the second windows:

do you get the same vsthost error message?
When this happen of course wineasio hang the system too.
I have press the OK and then run again the vsthost and work again.
Honestly I have to ask to debug for see where is the bug side.
Here also the new VstHost for test: http://www.lionstracs.com/download/update/vsthost147.rar
extract and replace with the old vsthost.exe on the main location:
usr/mediastation/current/bin/vsthost/vsthost.exe

I will report this bug to Hermann too.
let me know