Random characters generated by LCD during serial.read()
The character to the right of the 'A' on your LCD display does not correspond to any of the built-in character bitmap definitions (either on a EU or Chinese display).  This random pattern is likely one of the 8 programmable character bitmaps supported by the LCD that has not been defined yet (ASCII codes 0 to 7).

So, you're likely sending the LCD a character with a value between 0 and 7.  It's probably a good idea to filter out invalid characters before attempting to display them on your LCD.

Filtering Example:

char c = Serial.read();
if ((c &gt;= 32) &amp;&amp; (c &lt;= 128))
  lcd.write(c);