Hello,
It's something the programmer for some reason have forgot.
Ramp 1 is set to modulate the VCO's Frequencies. Ramp's modulate from 0-max. That mean the end of the modulation in this case will result in a different pitch.
Using Ramps for this kind of modulation will require frequency compensation in one way or another.
Or using Track with a Ramp as input and setting the default points in reverse to 63, 47, 31, 15, 0. In this case Track is the modulator but with Ramp as input for the track.
In this case perhaps a ENV could have been used instead of a Ramp modulation. Just use Decay only and a negative modulation amount.