Why doesn't PageCache give back the cache in a PJAX request?

Question

Yii

I can’t understand what the problem is, I use the behavior PageCache, if I just open the page (in the browser), everything caches ok, it returns instantly. But when using PJAX, for some reason, the request is processed again and takes the full processing time, although as far as I can see in the console, the usual GET is overgrown on the same controller that I open in the address bar.
ps
I'm using GridView (by kartik-v).