Mine started doing the same fault yesterday (26.9.2019).
I purchased mine through a 3rd party on Amazon on June 2019, so have contacted them and asking what options do I have.
After reading all the messages here, it seems to be a fault with the USB connecter to motherboard.
Mine replaced only the USB and when they brought it back, the whole thing was one big defect (no calls, no internet, warms up and battery drain). They took it back, replaced the whole motherboard and now it's ok.
The battery is weaker than before and I'm wondering whether I want to go to round 3...
Bottom line: it looks like Samsung needs to say something about this issue... for now it's one big silence from them.
We payed such a big amount for the name samsung. We haven't payed 70 thousand to let our cell phone open .we haven't payed for a repaired set. I refused to dismantle my set .samsung must indulge in this matter. I bought it box packed a month ago and this issue happened. Samsung must replace the complete set or atleast enable us to disable this dam notification usb connected disconnected. I hope to have a good responce from samsung very soon .
Engineer Bilal Ahmed