In regards to the 3rd party launcher, maybe try installing one to test to see if this happens with a 3rd party launcher. I use naval launcher and i dont have this issue. I also reverted back to using the stock launcher to test , and after a phone cache reset, i dont have the icon issue. This phone i have is a tmobile variant. Stock, and locked to tmobile.
Even though when you move an app to SD card, some dat still remains in internal memory and the app is not totally off the internal storage. If you are not at risk of low on board memory, perhaps give some serious thought to moving the apps back onto internal memory.
Other than a full factory reset and re-build of your apps, theres not much else you can do. I doubt the phone has any issues, but without being able to see your phone in person and fuss with it, its going to be a crap shoot over the internet on how to remedy.
I did a cursory search online and ive not found anyone about having an issue such as yours with a current model note 8 (or even a s8), or even any current phone, so this is not a wide spread issue and maybe something specific to you.
Oerhaps turning off battery saver mode and set the phone to performance to test. If you do this, clear phone cache and re-attempt.