I just bought my new S9 and it works perfectly, but I got a problem with Instagram, especially when I wanna comment or react a story from anyone's account. The problem it is that whenever I start writing or choosing the reaction, the IG story doesn't get paused, it just keeps playing. Sometimes the comment that I just made appears to show from another story. I don't know if it's a real problem from my phone, an app's malfunction, or it's how it normally works on this device because my previous phone was an iPhone.
I had this problem and I thought it was my phone but I noticed if you hold down on the story for a second, the same way you do to pause a story while reading it, it will allow you to then choose a reaction. Same with replying to a story or question, if you go to tap to reply straight away the story won't pause and cuts off your message. So simple answer, just hold down on the screen before replying lol
I have the same problem on my Samsung Galaxy S8. I was at a service point recently, they put on new software and now several programs show problems. This is one of them. Holding down the story doesn't help me! They keep playing while I'm typing my reply!