16x2LCD Display serial read extra character
The LCD display acts a bit different to a normal console. For instance, it does not recognize the newline character and uses the corresponding ASCII code (10) like a normal letter. Depending on the letter map of your display (for which there are several variants on the market) this will print a more or less random character. To avoid this, you have to strip the last letter from the input string before sending it to the display.
For the same reason, sending an empty string does nothing, since an empty string sends no letters. To clear individual characters in the display, you have to overwrite them with a space.