Vector scope does not update with masking

[Ilja24753905x20c]

Hi,

I'm struggling to make Adobe Premiere Pro to work correctly. When I mask a skin tone and switch to Lumetri scopes, Vector scope as any other scope is not updated, though in the tutorials on Youtube  I see that with masking the vector scope gets updated right away. But then if I move some frames in any direction, the scopes starts to get updated right away, is that normal? I try to attach an example with mask selected on a skin tone, but vector scope is still showing the whole scene. Thank you in advance!