Thanks I will report this. Meanwhile I found the bug, and I guess it is really a bug…
It works with all strings...
1) Take a guitar tuner or just listen - you should listen it
2) Play any tone at one string - e.g. D-String
3) Check the tuning with the guitar tuner - should be o.k.
4) Use Modulation (C1) Controller turn it to max. and stop playing the tone
5) Turn the Modulation down to zero (I doublecheck this with a midi monitor)
6) Check the tuning again - if it is not out of tune, repeat from 2)
I guess the problem is that the plugin unwanted remember the old modulation value after stop playing of the tone. And even if you turn your modulation controller to zero this tone reminds a wrong tuning out of the vibration effect caused by the modulation controller. And this leads to a wrong tuning of one string - even when I turn the controller to zero. To get the right tuning you have to actively play that string again, push your modulation controller high and back to zero. After that you can stop playing the string and it should be again in tune....
I will send it to the developers, hope they read this ...