I have definitely had the "the thing I was looking at right after the app opened disappeared after a few seconds and I can't find it again" experience /u/mfontani describes.
I just loaded Instagram and it did this. It’s probably not something you see because you open the app multiple times a day. You definitely run into it when you only open the app a few times a week.
I see the "new posts" pill if I've scrolled down into the cached content at all, but if I'm just looking at the first post I see the behavior everyone else is describing. It's still pretty annoying.
I have the latest version of the app (on iOS) installed and this literally just happened to me. I run into it nearly every time I open the app.
I also see if it the app is running in the background and I switch back over to IG. I can be in the middle of my feed and scrolling and after a few seconds it refreshes and I lose my spot.