Ok folks,
1) I have added and directed that track to a TTS VSTi and the same vibrato happened after a few bars.
2) I have discovered that the vibrato rate knob has a controller n.77 assigned to it as defaut for both VSTs: Orchestral and TTS.
3) After I have removed that controller n.77 in both VST the vibrato rate alteration disappeared.
4) There must be something with the controller n.77! And if so, why Sonar doesn`t show us that controller in the event list?
5) Maybe there must be something with Sysex information ?! Which I can`t see!
Thank you very much for your attention