Why does adding an additional parameter "Path to the previous page" change the number of page views so much?

Question

Google Analytics

I analyze the user's route to the page of interest to me.
To do this, I go to "Behavior / Site Content / All Pages" and in the advanced filter set the mask of the page I'm interested in, for example ^/gift/[0-9]+, I get the total number of "Page views" equal to 2,274,690

. After that, I add "Path to previous page" and get a total of "Page views" of 3,166,005.

Why is there such a big difference? What does it mean? Indeed, in theory, the number of page views should not change at all, I just add an additional column to analyze which pages come from to the already selected pages?

Answer 1

In theory, yes.
And logically - add the previous node and Google pluses all "passes" of users through this node to the current one, regardless of the further route.
Those. not "AND", but "OR" works ...
You need to look for the condition setting or write to Google ...

Answer 2

for complacency, read this
well and break your head about 0 unique page views in the second picture in the first line