I have the s9 as well, but I can put my phone up to my cheek and it's cool to the touch. The blue line still appears. So I dont think its overheating. More just letting us know it's doing something I guess.
I too have been seeing this on my Galaxy Note9. At first I thought it was an AI assistant listening to me. Which would be nice to know everytime Bixby thinks it hears me talking to it. But then again, that is also creepy. The game launcher thing makes sense as I only see it when in Minecraft Earth or Pokemon Go. But still obnoxious.
Somehow this only happens to me after my latest software update, which was a few weeks ago. I'm using the S9. Very weird. Checked everything else everyone suggested in the thread but I'm not sure what it might be.
My A9 2018 also while playing heavy games
Hi, I've noticed that sometimes while I'm playing a game on my s10e, an animated blue line briefly appears at the bottom edge of the screen, similar to edge lighting. Does anyone know what this is?
i dont know if its not too late but i think i figured it out on my Galaxy S20 U. i noticed the blue bar showing up and i went into the game boost settings and noticed the temperature setting was on "cooling" i think this is what it tells you. Its shows blue bar which means the phone is heating up so it goes into cooling mode and just lets you know because that can meand that game might run slower since its using less power to let the processor cool down.
After some testing on my Samsung Galaxy S9, I came to the conclusion that the blue line that appears at the side or the bottom of the device while gaming, is related to the Auto control feature of the Game booster. It mostly helps the phone to avoid high temperatures over 45°c .
I hope that my answer helps,