Hello Juergen!
I can reproduce the problem with the combination of vibrato and legato in the Solo Strings. This will be corrected with the next VSL Soundset Installer update. In the meantime I suggest, excluding the vibrato indication from playback (Inspector/uncheck play on pass 1). Vibrato is default for the Solo Strings anyway. Also the perf-legato articulation is with vibrato.
Best regards,
Andi
Vienna Symphonic Library