Yeah with Instagram I wouldn't be surprised if they just do this to annoy to into using their app. Where they can force timed ads (you have to watch an ad now for a few seconds before it continues).

I noticed another platform (wallapop, a kind of ebay/craigslist here in Spain) that does the same. It never works well in a browser, even in chrome. I think they're just trying to bully their users to their app, which has 30+ trackers in it.