When did that start for you? I've never seen that myself, I can keep scrolling as long as I want
I opened Instagram and scrolled now just to reproduce it again, and I saw one "normal" post before this "ad break" appeared for me: https://i.imgur.com/SS6kuKV.png
They're a punishment for you because you won't let them collect data.
FB app does that too.
I uploaded the image to https://i.postimg.cc/Cx6fYh8p/image.png instead, hopefully you're not on corporate network blocking the (used to be) shady .cc tld.
To add further humor on top of this, I think i.postimg.cc TLS certificate just now/yesterday expired??? Not sure if it's just me, but the certificate says it expired "Thu, 10 Sep 2026 20:49:55 GMT" although I did manage to upload the image, maybe different host...