GSC and its strange behaviour

OK, I have a site and it's in GSC and that's where I get some weird stuff.
I have one volatile page so to better understand what's going on I exclude it to see a better picture.
But that's what I get:
1. Total impressions: 34k
2. I exclude the volatile page and... my impressions are: 36k
(the page itself gets about 1.5k-20k impressions, yeah, it's very volatile, lately it's become more stable though)

So how is it possible to have more impressions after excluding a page?

That kind of weirdness in GSC happens more often than most expect, especially when you exclude a volatile page. The thing is, the numbers aren’t always derived from a simple subtraction. When you filter out a page, GSC often recalculates impressions dynamically and sometimes reassigns queries to similar pages due to overlap or split rankings.
Some users even test this with geo-targeted traffic via mobile proxies to see how impressions get distributed, and sure enough, GSC behaves differently depending on user origin, session quality, and intent clusters.