In subsonic flight, VS is constant with EAS. However, airliners fly at transonic regimes, in which compressibility has a double effect:
on the one hand, VS IAS increases with mach number, even if VS EAS remains constant.
Secondly, Lift and Drag Coefficient curves change with mach number, and VS EAS increase (separation occurs at an earlier AoA due to compressibility effects, shockwaves and such).
The overall result is a very noticeably increase in VS indicated.
Both VS and VaPROT are AoA based speeds, so when Mach number increases, both speeds increase.