Problem with Scale property alters the color gamut (verify in vectorscope)

Hello everyone, the problem consists in this, if I create a title in After effect and export it with alpha channel (Appla ProRes 4444 with alpha) with a lively color but within the limits of the legal Gamut (verified with vectorscope - See image 2) in the moment in which i change the ownership of the SCALE the values inherent to the Gamut rise becoming illegal (verified with vectorscope - See image 1).

Why does this happen? how can i fix it?

Thanks for reply!