Thats interesting... Maybe you installed the drivers for a display that does support 4k, this would trick windows into thinking its 4k. Could just be windows thinking that its a different model.
Does the model shown in windows dialogues show the same as your monitor?
No, there is no damage done to your graphics card or monitor, i think this is a purely firmware/software based thing. The only way that it COULD hard your graphics card is if it gets hot (over 90C) although some cards can get hotter and are made to get that hot.
All in all everything is fine, just a bug or glitch. Leave it at 1080p just incase
:Mathsnerds