Hello vosk!
I can't reproduce any error in the expression map "Synchron Strings I - Violins, Violas". Legato normal and legato fast work fine here with the preset "03 Violas-8 VelXF". Please make sure to always keep the root note at C0 in the Expression Map Setup window. Otherwise keyswitches will be shifted.
Best regards,
Andi
Vienna Symphonic Library