Just to emphasize, on a S8+ tablet with the original keyboard cover, the 5s trick worked. I get a message saying: "Fn Key Locked" and it changes the behavior as expected. Hopefully there's a way to make it work for you too, as I understand how frustr...

Greetings from Brazil. I bought a S8+ tablat that came with the Samsung Keyboard. The 5s trick worked really fine and solved the issue! Thanks for sharing, this is very usefull information!